WEBSPHERE INTERVIEW QUESTIONS COVERING ALL TOPICS

Interview questions and also find the realtime usage commands link at the end of the blog. Which will be helpful during the interview.

1. In a Web-based architecture, if you try to hit the URL, it shows an error like page cannot be displayed, How to troubleshoot this issue?

Ans: The Flow of Request happens from

Load Balancer >> Webserver >> Appserver >> DBso the investigation for such issues should also follow the same routes .. ( well thats how i follow )

Try to check if the url is responding from your end. (This will eliminate if its specific to a user or its error for every one)

Check the Webserver if its running or not, If it’s not running start it

Check if the application server and application is running.. if not start it

Try to access the Application directly from the Appserver .. ie using the http transport port. ie wc_defalut .. ( this will identify if the error is due to App server or is with the Webserver/plugin)

check for the errors in the Appserver and web server logs

Check for the config in the plugin file to ensure that the url which is being hit is avaliable in the plugin-xml.cfg ( If it is not then it could be possible that the plugin was not regeneraed ad propagated after the deployment)

Enable the trace in the plugin-xml.cfg to understand in the plugin logs whether the plugin is forwarding the req to the appservers or not

Lastly also check if the page which you are requesting is avaliable within the web modules.

2. Suppose in a cluster environment one of the servers is about to reach 100% CPU utilization, remaining servers are in normal utilization If this is a scenario then how it will occur and what is the reason for that case and how to resolve these kind things?

When i looked at the System out log , there are lot of threads are in hung state.

Solution:

Take the 3 thread dumps in interval of 1-2 mins. (Kill -3 PID)

Kill the that process ( kill -9 PID)

Restart the server/JVM

Analyze the dumps.

3. If client is complaining that app is slow, then wat is the steps which need to be followed up to resolve the issue?

Well there are many reasons for the slow behaviour

Check the CPU utilisation of the appserver and the entire server to see if there are cpu bottleneck(top command)

Check the Memory utilisation of the appserver and the entire server to see if there are memory bottleneck(Free -m)

Check the systemout.log to check if there are any hung threads or OOM

Check the heap allocated to the JVM

Check the connection to the DB , it could be possible that the connections to the DB has got MAXED out

Check the Plugin and webserver logs to see if its connection to has maxed

Take the thread dump for further analysis(kill -3)

4. Suppose we have 10 applications in our environment? How the request goes to particular application?

A request wills generally goto an exact application by the context root of that application.

5. What is the difference between the Generate Plug in and Propagate Plug in?

generate plugin:-if any changes are done in websphere environment then we have to do generate plugin(changes like:-change in virtual host, creating or deleting servers or clusters, deploying or deleting new application)to create the plugin we have a cmd bin/genplugincfg.bat->dmgr/bin directory) then it will be generated in the DMGR cell level.

Propogate plugin - It transfers the generated plugin to it respective remote webserver config path : <WEBSERVER_HOME>/Plugins/config.

6. When we synchronize node from cmd mode, why do we need to stop node agent. ?

To make sure no changes to the master configuration while performing full sync via cmd. If node agent Is up and someone else saving configuration which conflict to the full sync...

if did not stop node agent, then changes made by sync is not recognize and in next auto sync all these changes are overridden. because node agent sync is done only from dmgr. so it identifies only changes known by dmgr, if u do manually sync without stopping nodeagent ,then dmgr doesn't come to know these changes and those are overridden in next sync.

7. What is the difference between deploying an EAR File and WAR File?

• In ear files no need to give the context root...in war files u have to give
• EAR menace Enterprise application and WAR menace web application
• In WAR Auto Deployment is possible where else in EAR auto deployment is not possible
• WAR contains Web.xml file where EAR contain web.xml and Application.xml file

8. What is node group?

A node group is a collection of managed nodes. Nodes that you organize into a node group need to be similar in terms of installed software, available resources, and configuration to enable servers on those nodes to host the same applications as part of a server cluster

.A default node group called DefaultNodeGroup is automatically created for you when the deployment manager is created, based on the deployment manager platform. New nodes on similar platforms are automatically added to the default group. A node must belong to at least one node group, but can belong to more than one.

As long as you have nodes in a cell with similar platforms, you do not need to do anything with node groups. New nodes are automatically added to the node group. However, before adding a node on a platform that does not have the same capabilities as the deployment manager platform, you will need to create the new node group.

9. What is plug-in configuration file?

The web server plug-in configuration file controls whether an application server or the web server handles user requests. You must regenerate this global plug-in configuration file whenever you change the configuration settings for an application server, cluster, web container transport, or virtual host alias that is contained in the cell. You must also regenerate this file whenever you add a new application server, cluster, web container transport, or virtual host alias to the cell. The global plugin-cfg.xml file is placed in the %was_profile_home%/config/cells directory. This configuration file includes the URIs for all of the applications that are deployed in this cell. If your web server is located on a remote machine, you must manually move this plug-in configuration file to that machine.

10. What is Node Agent?

The node agent process serves as an intermediary between the application servers on the node and the deployment manager. The node agent process runs on every node and is specialized to perform node-specific administration functions, such as server process monitoring, configuration synchronization, file transfer, and request routing.

We can stop node agent , Retstart nodeagent and restart all servers on node from the console but we can't start from the console if it is stopped.

11. What is Deployment manager?

The deployment manager provides a single, central point of administrative control for all elements of the distributed cell.

we can stop the deployment manager from console but can't start if from the console.

12. Difference between Managed node and Unmanaged node ?

A managed node contains an application server process that runs within the deployment manager cell. The managed node is associated with a node agent process that maintains the configuration for the node and controls its operation. Choosing this option results in running the add node utility to federate an existing stand-alone application server.

An unmanaged node represents a node in the topology that does not have an application server process or a node agent process. Unmanaged nodes are for other server processes, such as web servers that exist on their own node in the topology.

13. Can you start node from the console?

no

14. What will happen if you stop the node from console?

It will stop all the process which are running under the node ( servers & nodeagent).

15. What is Buses

A service integration bus supports applications using message-based and service-oriented architectures. A bus is a group of interconnected servers and clusters that have been added as members of the bus. Applications connect to a bus at one of the messaging engines associated with its bus members.

16. What is application server?

An application server is a server that provides services required to run enterprise applications.

17. JMS providers

A JMS provider enables messaging based on the Java Message Service (JMS). It provides J2EE connection factories to create connections for JMS destinations.

18. Connection factories

A connection factory is used to create connections to the associated JMS provider. These connection factories can be used for accessing JMS Queue and JMS Topic destinations.

• Queue connection factories

A queue connection factory is used to create connections to the associated JMS provider of the JMS queue destinations, for point-to-point messaging.

19. Topic connection factories

A topic connection factory is used to create connections to the associated JMS provider of JMS topic destinations, for publish and subscribe messaging.

20. Queues

A JMS queue is used as a destination for point-to-point messaging.

21. Topics

A JMS topic is used as a destination for publish/subscribe messaging.

22. Activation specifications

A JMS activation specification is associated with one or more message-driven beans and provides configuration necessary for them to receive messages.

23. What are the differences between Queue and Topic ?

Queue:

•Point-to-point model

•Only one consumer gets the message

•Messages have to be delivered in the order sent

•A JMS queue only guarantees that each message is processed only once.

•The Queue knows who the consumer or the JMS client is. The destination is known.

•The JMS client (the consumer) does not have to be active or connected to the queue all the time to receive or read the message.

•Every message successfully processed is acknowledged by the consumer.

Topic:

•Publish/subscribe model

•Multiple clients subscribe to the message

There is no guarantee messages have to be delivered in the order sent

•There are no guarantees that each message is processed only once. -- As this can be sensed from the model

•The Topic, have multiple subscribers and there is a chance that the topic does not know all the subscribers. The destination is unknown.

•The subscriber / JMS client needs to the active when the messages are produced by the producer, unless the subscription was a durable subscription.

•No, Every message successfully processed is not acknowledged by the consumer/subscriber.

24. What is the use of garbage collector?

You can check the verboseGC report to determine:

How much time the JVM is spending performing garbage collection.

Ideally, you want the JVM to spend less than 5 percent of its processing time doing garbage collection. To determine the percentage of time the JVM spends in garbage collection, divide the time it took to complete the collection by the length of time since the last AF and multiply the result by 100. For example:

83.29/3724.32 * 100 = 2.236 percentIf you are spending more than 5 percent of your time in garbage collection and if garbage collection is occurring frequently, you might need to increase your Java heap size.

Two main technologies used to remove the garbage:

Mark Sweep Collector and Copy Collector

IBM uses a mark sweep collector (or) a combination for generational (gencon)

Garbage Collection can be broken down into 3 steps

a) Mark: Find all live objects in the system

b) Sweep: Reclaim objects that are no longer referenced

c) Compact: Converts many small holes into fewer large ones to avoid fragmentation

The first thing to notice here is the “action=” figure. Seven different actions can occur for an allocation failure:

action=0 means the pinnedFreeList was exhausted.

action=1 means a preemptive garbage collection cycle.

action=2 means a full allocation failure.

action=3 means that a heap expansion takes place.

action=4 means that all known soft references are cleared.

action=5 means that stealing from the transient heap is done.

action=6 means that free space is very low.

25. What is SSL?

The Secure Sockets Layer (SSL) is a protocol that provides secure communications between remote server processes or endpoints. SSL security can be used for establishing communications inbound to and outbound from an endpoint.

26. What are the siner certificates?

Signer certificates are used by Java Secure Socket Extensions (JSSE) to validate certificates sent by the remote side of the connection during a Secure Sockets Layer (SSL) handshake

27. What are the different GC policy algorithms in IBM WebSphere Application Server V8 ?

IBM WebSphere Application Server V8 (on supported platforms) provides four different GC policy algorithms:

-Xgcpolicy:optthruput

-Xgcpolicy:optavgpause

-Xgcpolicy:gencon( Default)

-Xgcpolicy:balanced

IBM WebSphere Application Server V7 (on supported platforms) provides four different GC policy algorithms:

-Xgcpolicy:optthruput ( Default)

-Xgcpolicy:optavgpause

-Xgcpolicy:gencon

-Xgcpolicy:subpool

28. What are the plugin parameters?

ConnectTimeout, ServerIOTimeout, RetryInterval, IgnoreAffinityRequests, LoadBalanceWeight, MaxConnections.

ConnectTimeout identifies how long (in seconds) the plugin will wait to get connect to WebSphere Application Server (WAS). If the plugin waits longer than the value, it will mark the server unavailable.

By default (without the parameter set in the plugin-cfg.xml) or setting the value to 0, it represents a blocking connect, that is, the thread will keep waiting to obtain a connection until the operating system time out the request.

ServerIOTimeout identifies how long (in seconds) the plugin will wait for the server to response to the request. If the plugin waits longer than the value before the response is completed, it will time out.

By default, the plugin uses blocked I/O. So basically it will block wait until TCP connection times out.

RetryInterval is the time that the plug-in will wait before trying again to use an appserver that was marked down.

MaxConnections : Max no. of pending connections/requests for App server ,When the MaxConnections limit is reached, the plug-in will stop sending requests to that appserver, but it is not marked down

Please note that if the MaxConnections limit has been reached the plug-in will not send ANY more requests to that server until responses come back for the current PENDING requests, and the pendingRequests count drops back down below the MaxConnections limit.

29. How do you Determining whether OOM is a Java OOM or Native OOM ?

If the stdout/stderr message says that this is a java.lang.OutOfMemoryError, then this is a Java OOM.

If the stdout/stderr message says that it failed to acquire memory, then this is a Native OOM.

30. What is the effect of changing max heap and min heap size of a jvm same?

Using the same values is not usually a good idea, because it delays the start of garbage collection until the heap is full

Compaction moves objects closer and further down in the heap, creating larger free areas near the top of the heap

Max memory used should be about 55-75% of the max heap size.

31. What is nursery heap?

The nursery is a part of the heap reserved for allocation of new objects.

32. Why and when to perform name space binding?

Name space binding is used to provide fixed qualified names for server application objects.

A deployed application requires qualified fixed names if the application is accessed by thin client applications or by J2EE client applications or server applications running in another server process.

When you configure a name space binding, you create a qualified fixed name for a server object. A fixed name does not change if the object is moved to another server. A qualified fixed name with a cell scope has the form: cell/persistent/fixedName

33. Name space Binding types ?

1) String 2) EJB 3) CORBA 4) indirect

34. What is Heap dump ?

A heap dump is a snapshot of the memory of a Java process at a certain point of time. It shows live objects in the memory and references between them.

You can use this option to debug conditions such as memory leaks, heap fragmentation or to investigate what objects are consuming the largest part of the memory

35. What is Thread dump ?

A thread dump is a list of all the Java threads that are currently active in a Java Virtual Machine (JVM).

36. What is core dump and How to enable Core Dump function in linux?

A core dump is the printing or the copying to a more permanent medium (such as a hard disk ) the contents of random access memory ( RAM ) at one moment in time.

A core dump is taken mainly for the purpose of debugging a program

enable core dump

If you enter “ulimit -c” command and get the result value as 0, it indicate that core dump is disabled by default, it would not generate core dump file.

We can use the command “ulimit -c unlimited” to enable the core dump function, and does not limit the core dump file size; if you need to restrict the size of the file, change the “unlimited” as you want to generate the core file maximum size, pay attention to the unit is blocks (KB).

Using the above command will only effective for terminal current environment， if you want to be permanent, you can modify the file /etc/security/limits.conf file. add the below one line:

# /etc/security/limits.conf

#

#Each line describes a limit for a user in the form:

#

#&lt;domain&gt; &lt;type&gt; &lt;item&gt; &lt;value&gt;

<span style="color: #008000;"> * soft core unlimited</span>

37. What is the use of generic JVM arguments?

The generic JVM arguments are used to configure and adjust how the JVM executes. Once changes are made and saved to the master configuration, the JVM requires a restart for the arguments to take effect. Each JVM argument is separated by a space. This is also called it's delimiter

or

Generic JVM arguments Specifies command line arguments to pass to the Java virtual machine code that starts the application server process.

Add the generic Jvm Arguments using the WebSphere Admin Console or by editing the server.xml file:

Application Server

• In the Administration Console select Servers
• Expand Server Type and select WebSphere application servers
• Click on the name of your server
• Expand Java and Process Management and select Process Definition.
• Under the Additional Properties section, click Java Virtual Machine.
• Scroll down and locate the textbox for Generic JVM arguments.

1.Open the following file:

install_root/IBM/WebSphere/AppServer/profiles/AppSrv01/config/cells/<cellName>/nodes/<nodeName>/servers/server/server.xml

2.Find the jvmEntries element.

3.Add the following JVM options to genericJVMArguments in server.xml and save the file:

genericJvmArguments="-Djava.awt.headless=true -DamCryptoDescriptor.provider=IBMJCE

-DamKeyGenDescriptor.provider=IBMJCE -Djavax.management.builder.initial= /-Dcom.sun.management.jmxremote"

38. What is core group?

A core group is a grouping of WebSphere(R) Application Server cell processes. A core group can contain stand-alone servers, cluster members, node agents, and the deployment manager. A core group must contain at least one node agent or the deployment manager.

DefaultCoreGroup is a core group that is created by default at installation time and can be used out-of-the-box; that is, all processes will know about each other.

Note:

1. A core group cannot extend beyond a cell

2. All JVMs in a core group must able to communicate (they use heartbeat messages to know each other

A core group must be empty before it can be deleted. The default core group cannot be deleted.

Each core group contains a core group coordinator to manage its high availability relationships, and a set of high availability policies that are used to manage the highly available components within that core group. You can move processes from one core group to another.

The following rules govern the core group membership:

•Every process is a member of exactly one core group.

•All members of a cluster must be members of the same core group.

•Each core group must contain at least one node agent or the deployment manager.

Core group coordinator: The core group coordinator is responsible for coordinating high availability activities between the core group members for which View Synchrony Protocol is established.

We can change the default core group coordinator by going to:

servers –>coregroups->coregroup settings->Default Coregroup ->preferred coordinator servers.

When a member becomes active coordinator, you can see the following messages in the SystemOut:

[3/3/10 18:00:37:758 CET] 00000013 CoordinatorIm I HMGR0206I: The Coordinator is an Active Coordinator for core group DefaultCoreGroup

If a new member joins the core group, you can see the following message

[3/3/10 18:17:13:245 CET] 00000026 RoleMember I DCSV8051I: DCS Stack DefaultCoreGroup.TestRepln at Member Test-Cell\node01\server01: Core group membership set changed. Added: [Test-Cell\node02\server02]

39. How do you decide which WebSphere Application Server process should be a core group bridge?

Any WebSphere Application Server process (dmgr, node agent, application server) can be a core group bridge process for a core group. However, a process that you choose to be a core group bridge should have production activities or response times that will not be affected by the core group bridge workload. Node agents or application servers that do not host any applications can be used as bridges, but it is best to use dedicated non-clustered application servers that do not host applications, if available system resources permit.

The dmgr process is similar to node agents in that it does not handle real-time production traffic. However, because dmgr represents a single point of failure and likely administers a large number of servers in a topology with multiple core groups, it is best for it not to have the added task of being a core group bridge.

40. What happens when coordinator went down?

When the active coordinator is not available (stopped/crashed), the HA manager will elect the first inactive server in the preferred coordinator servers list. If preferred list is not specified, it will select lexically lowest named server.

The newly selected coordinator initiates a state rebuild by sending a message to all core group members to report their states.

41. Which servers need to be restarted after making core group bridge configuration changes?

Core group bridge configuration changes are not dynamic, and any time a bridge configuration change is made, all of the affected bridges need to be restarted. Also, bridges can only communicate with other bridges that have the same access point group configuration. Consider this topology under different scenarios:

DefaultAccessPointGroup contains:

CoreGroup1:

Bridges: bridgeServer1,bridgeServer2

Servers: cluster1Member1, cluster1Member2

CoreGroup2:

Bridges: bridgeServer3,bridgeServer4

Servers: cluster2Member1, cluster2Member2

CoreGroup3:

Bridges: bridgeServer5,bridgeServer6

Servers: cluster3Member1, cluster3Member2

Scenario A: CoreGroup4 and bridges bridgeServer7 and bridgeServer8 are added to DefaultAccessPointGroup

The other six bridges (bridgeServer1, bridgeServer2, bridgeServer3, bridgeServer4, bridgeServer5, and bridgeServer6) will need to be restarted to recognize the new bridges in CoreGroup4. Otherwise, CoreGroup1, CoreGroup2, and CoreGroup3 will continue to communicate and exclude CoreGroup4, because CoreGroup4’s bridges have a different access point group configuration defined.

Scenario B: Bridge bridgeServer2 is stopped and removed from CoreGroup1; Bridge bridgeServer2b is added as a bridge in CoreGroup1 to replace bridgeServer2

Bridges bridgeServer1, bridgeServer3, bridgeServer4, bridgeServer5, and bridgeServer6 will need to be restarted when bridgeServer2b is brought online. Otherwise, they will not be able to communicate with bridgeServer2b.

Scenario C: Cluster1 (cluster1Member1 and cluster1Member2) gets moved from CoreGroup1 to CoreGroup2

Bridge configuration was not changed and no bridges were moved, so none of the bridges need to be restarted. Only the cluster1 members will need to be restarted when moved to CoreGroup2.

42. With regard to server startup sequence, when should the core group bridges be started?

A core group bridge does a significant amount of work during startup. Using the proper server startup sequence can reduce the amount of work that is done. The optimum order is:

1.Core group coordinators

2.Core group bridges

3.Clusters and other servers

Data is evenly distributed between active core group bridges, and each time a bridge is started or stopped, the data has to be redistributed. Therefore, it is more efficient to start the bridges early on when there is little data (fewer servers started to post data) in the core group to redistribute.

43. How will core gorup identify Core group member Failure detection

HA manager monitors all the core group members. It uses 2 settings to detect the failure

1. Active failure detection

If the heartbeat from a JVM is failing for specified interval of time, then it will be marked as failed. When using default settings, heartbeats are sent every 10sec and 20times (200sec) should be failed before marking the JVM as failed. When a JVM is marked as failed, a new view is installed and you can see that in the SystemOut log.

2. TCP Keep Alive

If one member is not able to contact other member, and if gets closed socket error, it will signal the other members to treat that member as failed. Say, if one jvm is panics or network issue etc, as soon as the TCP settings allow, the failure will be detected.

Note: TCP Keep alive setting is of the operating system.

44. Difference between Java heap and Native heap memory

Java heap is the memory that the JVM uses to allocate java objects.

Native heap is the memory that the JVM uses for its own internal operations. JVM uses this area to load libraries and for intermediate code generation.

Not all addressable memory is available to a process. The operating system has its own requirements such as

1) The Kernel and 2) The runtime support libraries

The addressable memory remaining is often referred to as user space.

We define the native heap as Native heap ="user space” - maximum Heap Size

45. What is PermGen(Permanent Generation) Area ?

It is the area where class loading and unloading happens. it stores metadata about classes , methods,etc.

46. What is Old generation area?

The largest memory pool which should keep the long living objects

47. What is inside a WAS plugin configuration file?

Virtual host information

Cluster and Cluster member information

URI mappings

Cluster loadbalancing algorithm

Plugin kdb ssl mappings

48. What is the WAS plugin configuration file name?

plugin-cfg.xml

49. What is the configuration file for IHS?

httpd.conf

50. What is the httpd.conf file in IHS ?

This is the main IBM HTTP server configuration file. It contains the configuration directives that give the server its instructions.

ServerRoot "/opt/IBM/HTTPServer"

PidFile /srv/jas/logs/gpsprod/HTTPServer/prod0/httpd.pid

PidFile: The file in which the server should record its process identification number when it starts.

DocumentRoot "/srv/jas/data/gpsprod/HTTPServer/prod0/htdocs"

DocumentRoot: The directory out of which you will serve your documents. By default, all requests are taken from this directory, but symbolic links and aliases may be used to point to other locations.

51. What are the performance tuning parameter for IBM IHS?

ThreadLimit: maximum setting of ThreadsPerChild

ServerLimit: maximum setting of StartServers

StartServers: initial number of server processes to start

MaxClients: maximum number of simultaneous client connections

MinSpareThreads: minimum number of worker threads which are kept spare

MaxSpareThreads: maximum number of worker threads which are kept spare

ThreadsPerChild: constant number of worker threads in each server process

MaxRequestsPerChild: maximum number of requests a server process serves

ThreadLimit 256

ServerLimit 4

StartServers 2

MaxClients 600

MinSpareThreads 25

MaxSpareThreads 75

ThreadsPerChild 32

MaxRequestsPerChild 0

52. How do you gracefully shut down IHS?

In IHS 7.0 and later on Unix, apachectl -k graceful-stop will stop listening for new requests but allow active requests to finish, waiting forever by default, or until GracefulShutdownTimeout seconds have elapsed.

Otherwise, there is no mechanism to shut down the web server yet allow active requests to gracefully finish. Active requests must finish within about 7 seconds, or they may be forcefully terminated when the child process is killed.

53. How does IBM HTTP Server determine when a child process should end? Does it have a timeout?

There is no timeout .If MaxRequestsPerChild is set to non-zero, a child process will exit once it has handled that many client connections.

While there are more idle processes than the value of MaxSpareServers, one child process will exit per second.*

require starting as root, or changing the ownership or permission of existing log files, depending on the configuration.

54. What happens if I stop IBM HTTP Server using SIG KILL?

Stopping the server by sending SIGTERM to the parent process

•no new connections will be accepted, starting almost immediately

•existing requests will have a short time to finish and log their results

•for most child processes: ◦the active request will finish normally

◦the active request will be logged

•for child processes that don't finish their request in a reasonable amount of time: ◦the request will be abruptly terminated

◦the active request won't be logged

Stopping the server by sending SIGKILL to all of the processes

•no new connections will be accepted, starting almost immediately

•all active requests will be abruptly terminated

•no active requests will be logged

•the pid file won't be removed, so a warning will be logged when the server is started again

•no permanent problems expected

•Note: Third-party modules could require manual intervention before restart if they have resources that they must release at termination.

55. Why are httpd processes still active when apachectl stop completes?

apachectl stop sends a signal to the parent process, and then exits. As soon as the parent process receives the signal, it starts terminating the child processes. In many cases, by the time you can look for child processes after the completion of apachectl stop they will have already exited. Some of the following are reasons why they will linger for some time:

•high system load (perhaps caused by many httpd child processes having to wake up and exit

•active requests being handled by one or more httpd child processes

56. what are the log levels in HIS

LogLevel: Control the number of messages logged to the error log. Possible values include: debug, info, notice, warn, error, crit, alert, emerg.

1) When i uninstall and installing the application it was saying that application is already exist but it is not there in the installed path and console .

then i check in the temp folder the war file was not deleted so i deleted the war file from the temp and synchronized the nodes then issues resolved.

2) when i start the application it was not coming up , then i check the logs i noticed Class not found error then i checked the shared libs in the console and in the putty path , some jars files are not there in the putty path then i asked application team some jars files are not present in the path.

3) application team reported that application is not responding when i check the logs i could see no space left error .when i check whilc file system one of the file system was 100% then i identified and removed unwanted files then issue got resolved.

4) when i try to uninstall the application it was unable to install

1) Deploy the application

2) configuration changes like jvm setting , connection pool settings

3) enabling traces

4) Generate and propagate the plugin to webserver.

5) creating the resources like jdbc providers and datasources.

6) Resolving the issues

57. Installing a fix pack with silent install on was 7.

This will describes how to use the Update Installer for WebSphere Software to install the fix pack using the silent install option.

Before you begin

The most recent version of the Update Installer needs to be installed on a target system locally.

Use the Update Installer program from the same user ID that installed the product that you are updating. Otherwise, the file ownership mismatches might require correction by the root user. 

About this task

The most recent version of the Update Installer needs to be installed on a target system locally.

Procedure

1. Download the required fix pack from the official IBM support Web site into< WAS-ROOT>/maintenance directory.
2. Ensure that all running processes have been stopped.
3. Edit a response file. The one located at the bottom of the pane can be used as an example. There are also sample response files found in the <WAS-ROOT>/responsefiles directory.
   1. Specify the location of the product to the response file.
   2. Specify the choice of install maintenance in the response file. For example: -W update.type="install"
   3. Add the maintenance location where packages can be found to the response file.

When you install the fix pack, certain logic is used to determine which packages to install. To find out more, refer to "Logic that the Update Installer uses for system recommended installations," found at the bottom of this topic.

4. Run the Update Installer.

For example:

Windows

update.bat -silent -options "responsefiles\file_name"

Vista

update.exe -silent -options "responsefiles\file_name"

AIX, Linux,Solaris

./update.sh -silent -options "responsefiles/file_name"

5. Review the log file to verify maintenance has been installed successfully. The log can be found atapp_server_root/logs/update/maintenance_package.install. If for some reason the maintenance package is not applicable to install, a log file found in <WAS-ROOT>/logs/tempX will list the reason for the failure. The most recent log file, tmpX, where X refers to the first available empty directory, will be created to reflect the status for this attempted install. You might not receive an error message for a failed installation in some cases. If you silently install a maintenance package and you do not receive a response after a short period of time, view the logs. If logs are not generated, then an invalid or missing argument might be causing the installation to fail. Verify the Update Installer syntax for the command line with the response files install.txt and uninstall.txt, located in <WAS-ROOT>/responsefiles

Results

One of the following results will appear in the log.

INSTCONFSUCCESS

The operation was a success.

INSTCONFPARTIALSUCCESS

The operation was partially successful, refer to the log for more details.

INSTCONFFAILED

The operation failed; refer to the log for more details.

58. What is new in WebSphere 8

1) Java virtual machine settings

Version 7.0 and previous versions use the optthruput garbage collection algorithm. In Version 8.0, the default is set to the generational garbage collector. This garbage collection algorithm can increase performance. The following JVM option is added to the WebSphere Application Server startup command: -Xgcpolicy:gencon. If you prefer to use the optthruput garbage collection alogorithm, you can remove -Xgcpolicy:gencon and the default optthruput garbage collection algorithm is used.

2) Application Server property settings for a web server plug-in

The Use read/write timeout setting on the administrative console corresponds to the ServerIOTimeout attribute in the plugin-cfg.xml file. The default for the setting and the attribute for Version 8 is 900 seconds. For Version 7, the default is 60 seconds. Before Version 7, the default is 0.

3) Track admin changes

Another new administrative function is the ability to track administrative configuration changes. This function leverages the Extended Repository Checkpoint function from WebSphere Virtual Enterprise, which writes out a delta repository each time configuration changes are saved to the WebSphere Application Server configuration repository. The delta repository lists the “before” and “after” configuration elements which can then be used to track configuration changes.

59. Installing and uninstalling a fix pack with silent install on WebSphere 8 ?

To install a fix pack from a service repository, perform the following actions:a.Log on to your system.

1) Stop all servers and applications on the WebSphere Application Server installation that is being updated.

2) Change to the Installation_Manager_binaries/eclipse/tools directory, where Installation_Manager_binaries is the installation root directory for the Installation Manager.

3)Install the fix pack.

[AIX] [HP-UX] [Linux] [Solaris] ./imcl install offering_ID_offering_version,optional_feature_ID

-repositories source_repository

-installationDirectory product_installation_location

-keyring keyring_file -password password

-acceptLicense

example : /opt/IBM/InstallationManager/eclipse/tools/imcl install 8.0.0.0-WS-WASJavaSDK-LinuxX64-IFPI20798 -installationDirectory /opt/IBM/WebSphere/AppServer -repositories /tmp/20140924/base_products/multi/IBM

To uninstall

root@iedcajcdwia2:/root : /opt/IBM/InstallationManager/eclipse/tools/imcl uninstall 8.0.0.0-WS-WASJavaSDK-LinuxX64-IFPI19109 -installationDirectory /opt/IBM/WebSphere/AppServer

60. How to copy files from one server to another server?

Use scp command

To copy a file from B to A while logged into B:

scp /path/to/file username@a:/path/to/destination

To copy a file from B to A while logged into A:

scp username@b:/path/to/file /path/to/destination

61. Is it possible to run IBM HTTP Server as a non-root process on UNIX systems?

It is possible to run IBM HTTP Server as a non-root process on a UNIX system, but when doing so, use only nonstandard ports above 1024 and define user/group in the httpd.conf process.

When you start Http webserver as a wsadmin(non-root) account we will get below error

(13)Permission denied: make_sock: could not bind to address [::]:80

(13)Permission denied: make_sock: could not bind to address 0.0.0.0:80

No listening

62. What information is available in plugin cfg.xml file ?

Plugin.cfg.xml file contains detail information about the application server

Plugin.config.xml contains the below information...

1) Server configuration,

2) Cluster configuration,

3) Server weights,

4) Application virtual host.

63. Why do I need to enable SSO when using form-based login in my WebSphere Application Server application?

By enabling SSO, WebSphere Application Server maintains user state as an LTPA cookie across Web requests. If SSO is not enabled, each individual request requires authentication. If you choose to use form-based login, once the form completes authenticating, the user then redirects back to the originally requested URL. Without SSO, the user's authentication is now lost and the authorization will fail. This is not seen when using basic authentication because the authentication information is in every HTTP request and WebSphere Application Server can use it whenever needed (this does impact both security and performance).

64. What is signer certificates?

A signer certificate represents a certificate and public key associated with some personal certificate. The purpose of the signer certificate is to verify personal certificates

65. What is personal certificates ?

A personal certificate represents the identity of the end point and contains a public and private key for signing/encrypting data.

66. What is a Keystore file ?

The keystore file is a key database file that contains both public keys and private keys. Public keys are stored as signer certificates while private keys are stored in the personal certificates. The keys are used for a variety of purposes, including authentication and data integrity. You can use both the key management utility (iKeyman) and the keytool utility to create.

67. What is Truststore file ?

A truststore file is a key database file that contains the public keys for target servers. The public key is stored as a signer certificate. If the target uses a self-signed certificate, extract the public certificate from the server keystore file. Add the extracted certificate into the truststore file as a signer certificate. For a commercial certificate authority (CA), the CA root certificate is added. The truststore file can be a more publicly accessible key database file that contains all the trusted certificates

Default self-signed certificate configuration

By default, WebSphere Application Server creates a unique self-signed certificate for each node.

WebSphere Application Server no longer relies on the default or dummy certificate that is shipped with the product. The key.p12 default keystore and the trust.p12 truststore are stored in the configuration repository within the node directory.

All of the nodes put their signer certificates in this common truststore (trust.p12).

Additionally, after you federate a node, the default SSL configuration is automatically modified to point to the common truststore, which is located in the cell directory. The node can now communicate with all other servers in the cell.

All default SSL configurations contain a keystore with the name suffix DefaultKeyStore and a truststore with the name suffix DefaultTrustStore.

These default suffixes instruct the WebSphere Application Server runtime to add the signer of the personal certificate to the common truststore. If a keystore name does not end with DefaultKeyStore, the keystore signer certificates are not added to the common truststore when you federate the server.

You can change the default SSL configuration, but you must ensure that the correct trust is established for administrative connections, among others.

For more information, see Default self-signed certificate configuration and Web server plug-in default configuration

The default password for the keystore is WebAS. You can change the default keystore password by using either the administrative console or the appropriate AdminTask command.

68. We have some issue with our application server and we tried killing it using kill-9 command, the process disappeared for few seconds but it is back again. We did not start the server but it started. What would be the reason?

Servers --> Application Servers --> server_name. Then, under Server Infrastructure,

click Java and Process Management --> Process Definition --> process --> Monitoring Policy.

Here we have an option Automatic Restart, this Specifies whether the process should restart automatically if it fails. On distributed systems, the default is to restart the process automatically.

69. Why can't we start node agent from console in websphere application server?

Node agent is a interface, communicator b/w servers and dmgr.. But there is not interface between dmgr and nodeagent. nodeagent behaves like manager to itself..once you start the nodeagent you can give commands like stop, start jvms in the similar way you can stop and restart the node agent as it is running..if nodeagent stopped, if you are issuing command like start nodeagent which process is going to receive the command.

70. How to get the password of .kdb file if we forget?

Once you have create the .kdb file this file related passwords are stored into .sth file it will be stored into the same directory.in the .sth file contains the .kdb file password in encrypted format.

71. How i can know how many users are hitting the application? If any command is there to find out the hit-counts?

You have to check in error.log

Using monitoring tool introscope willy

72. How will find out request is static or dynamic by webserver?

The way it works is first you install web server and copy your static content such as .js, .css files, images on the web server. Then you install a plug-in on web server. Plug-in takes a look at the incoming request and depending on the URL it decides if this is the request for static content or dynamic content, if it is request for dynamic content it forwards control to WAS.A web server plug-in is specific to the type of web server. It is installed on the web server machine and configured in the web server configuration.

73. How we can check application is running or not in websphere by command line utilities ?

grep the application name in systemout.log.

74. Is there a way i can start my server along with nodeagent ?

Servers--> Application Servers --> server_name. Then, under Server Infrastructure,

click Java and Process Management --> Process Definition --> process --> Monitoring Policy.

Here we have an option Node Restart State which specifies the desired behavior of the servers after the node completely shuts down and restarts.

STOPPED - node agent does not start the server.

RUNNING - the node agent always starts the server.

PREVIOUS - the node agent starts the server only if the server was running when the node agent stopped.

75. How to take the backup of EAR or WAR file using command line?

76. What is the command to see the content of zip file without extract?

77. What is the DocumentRoot in webserver?
78. What is Hybrid horizontal and vertical clustering?

For realtime commands and basic usage commands

https://webspherekarthiknotes.blogspot.com/2019/12/basic-commands-in-real-time-for.html

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