WebSphere ties to IP address? - Websphere

This is a discussion on WebSphere ties to IP address? - Websphere ; Hi, I was just testing around with websphere. What I did is I installed a dmgr on machine A, and a custom profile(Custom01) on machine B. Node federation of profile Custom01 to dmgr on machine A worked well. What I ...

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Thread: WebSphere ties to IP address?

  1. WebSphere ties to IP address?

    Hi,

    I was just testing around with websphere. What I did is I installed a dmgr on machine A, and a custom profile(Custom01) on machine B. Node federation of profile Custom01 to dmgr on machine A worked well.

    What I want to know if it will still work if I were to change the IP address of machine B, since I have the impression that websphere always ties up with the hostname, and not the IP address. So I changed the IP address and start the node. But from the admin console it says that the nodeagent is inactive.

    So I tried to create another custom profile(Custom02) on machine B, federate it to dmgr on machine A, but it failed. Federation will fail even after I changed the IP back to its original IP address. Even though it successfully connected to the dmgr machine, based on the error it says that the deployment manager cannot lookup by name host at adress . Hosts files on both machines were updated with the new IP.

    So I assumed this is how websphere works, since I stumbled the same issue on AIX servers. I ended up reinstalling websphere on the custom profile machine and federate it to the dmgr on a separate machine. No issues on local nodes.

    Is there a workaround on this problem without having to reinstall websphere all over again?

    Thanks.

  2. Re: WebSphere ties to IP address?

    did you restart the dmgr after the change of the ip-address of machine B?
    There could be cached information in one of the processes of the dmgr. A
    change of ip-address should work without any problems.

    Henk



  3. Re: WebSphere ties to IP address?

    gadidot@gmail.com wrote:
    > Hi,
    >
    > I was just testing around with websphere. What I did is I installed a dmgr on machine A, and a custom profile(Custom01) on machine B. Node federation of profile Custom01 to dmgr on machine A worked well.
    >
    > What I want to know if it will still work if I were to change the IP address of machine B, since I have the impression that websphere always ties up with the hostname, and not the IP address. So I changed the IP address and start the node. But from the admin console it says that the nodeagent is inactive.
    >
    > So I tried to create another custom profile(Custom02) on machine B, federate it to dmgr on machine A, but it failed. Federation will fail even after I changed the IP back to its original IP address. Even though it successfully connected to the dmgr machine, based on the error it says that the deployment manager cannot lookup by name host at adress . Hosts files on both machines were updated with the new IP.
    >
    > So I assumed this is how websphere works, since I stumbled the same issue on AIX servers. I ended up reinstalling websphere on the custom profile machine and federate it to the dmgr on a separate machine. No issues on local nodes.
    >
    > Is there a workaround on this problem without having to reinstall websphere all over again?
    >
    > Thanks.


    In addition to Henk's suggestion, make sure that DNS and /etc/hosts do
    not disagree with each other, I've seen that cause issues.

    Ken

  4. Re: WebSphere ties to IP address?

    Did you try doing a manual resync to the dmgr ?

    Don't know if it would work or not. Just a suggestion.....

  5. Re: WebSphere ties to IP address?

    Since you talk about custom profiles I know you are in 6.0 or later. What version are you looking at?

    When you create a profile, it asks for the "hostname or IP" of the machine the profile is on. If you are using the GUI profile creation tool it runs the 'hostname' command in the background and fills in what should be a correct value.

    If you supply an IP address during the profile creation the IP address will be used in various WebSphere configuration files and you likely will not be able to change IP address.

    If you supply a hostname during profile creation you should be able to change IP address. I assume that when you try to change IP address to a new value and then back to the original that nothing changed about your DM profile and original custom profile that had been working. If this is the case it may point somehow to your networking configuration.

    Just a thought but maybe you need to cycle the network adapter or connection after changing the hosts file?

    Also double check that the node agent for the original custom profile is running with the 'startNode' command from that profile.

    There is also a "Discovery protocol" that is used by the dmgr and node agents to find each other. If you know both processes are running but the dmgr shows the node agent as stopped in the admin console perhaps something at the network level is causing problems with this discovery?

    The 'synchNode' command you can run from the custom profile to manually resynchronize configuration between dmgr and custom profile is certainly one thing to try as someone else suggested. The issue is that if nothing about the configuration files changed this will likely not solve the problem.

    I would investigate why the original profiles you had configured and working lost communication after changing IP address.

    Federating a new node is a little different. When you run the 'addNode' command for a profile the profile asks "how would I resolve my hostname to an IP address?" and then sends that IP address to the dmgr to communicate back to the profile. This can cause problems if there is an alias for the machine B hostname to the loopback adapter on machine B as the addNode process would try to give the dmgr running on machine A an IP address of 127.0.0.1 which obviously won't work from machine A.

    The company I work for delivers a lot of WebSphere administration training that we have to run in environments where we don't have full control of networking. This means that we usually resort to "poor man's networking" using the hosts file which sounds like what you are trying to do so I know it is possible.

    Hopefully this is some info to help you keep troubleshooting. Let us know what you find out.

    Thanks,
    Stuart Smith
    Administration Lead
    Web Age Solutions
    www.webagesolutions.com

  6. Re: WebSphere ties to IP address?

    Sorry, I forgot to mention which version am using. It's WASND 6.1, machine A is on Ubuntu, machine B is on Fedora. No fixpack since am just testing for this IP/hostname thing.

    If am not mistaken with v6.0.2 and earlier versions, the GUI will ask for the IP or hostname, but 6.1 doesn't have that anymore. Unless if you're doing a silent mode installation, you'll get the chance to fill up either the IP or hostname. Am using the manageprofiles.sh command for this testing.

    "Just a thought but maybe you need to cycle the network adapter or connection after changing the hosts file?"
    Sorry but what do you mean by 'cycle' the network adapter? Restart the network service?

    "Also double check that the node agent for the original custom profile is running with the 'startNode' command from that profile."
    Yes, I run the startNode command from the specific profile directory.

    "This can cause problems if there is an alias for the machine B hostname to the loopback adapter on machine B as the addNode process would try to give the dmgr running on machine A an IP address of 127.0.0.1 which obviously won't work from machine A."
    I don't have the machine B hostname assigned to the 127.0.0.1 in the hosts file.


    Am actually kinda confused now because I've created too many profiles and kept on switching IP, and I didn't jot down any notes so am not able to provide a test case scenarios as for now.

    But just now I was using IP 10.8.8.61, created a profile (and this time I specified the parameter -hostName, I didn't specify this parameter on previously created profiles), federate it to machine A (10.8.8.31), and it failed. I was dumbfounded since 10.8.8.61 is the original IP of the machine. I remember booting up the machine this morning with a different IP address assigned to it (10.8.8.62) though. So I changed the IP back to 10.8.8.62, federate it, and it worked. Hmmm..

    Then I stopped the node, switched back to IP 10.8.8.61, sycned the node and started it, and it worked too. Prolly the -hostName flag did the trick? Why wouldn't it work the first time though?

    Oh well, I switched back to 10.8.8.62 and now the node is indicated as inactive in the admin console even though it started off successfully. Sounds like a network issue but ping is ok and even the port 8879 can be telnet.

    Think am gonna do a re-test. And this time I'll jot down some notes. I'll post again when am done with it.

    Thanks.

  7. Re: WebSphere ties to IP address?

    By "cycle" the network adapter I did mean restart the network service. Just something to make sure it is not still using the IP address that was in the hosts file previously.

    Even though it doesn't say it is required, all the examples of the manageprofiles command use the '-hostName' parameter.

    Since this parameter is not required the profile creation probably tries to get a value for the hostname automatically if you don't supply it. Perhaps there is some difference between the value it is getting automatically and the value you supply.

    Sometimes things will behave differently if you use a "short" hostname or a domain-qualified long hostname. I'm not sure what values you are using but it might be another source of differences between the profiles.

    It is definitely an issue of the network and WebSphere not getting along. You should be able to switch IP all you want. You clearly see this behavior sometimes but it doesn't seem to be predictable whether it will work or not.

    Let us know if you do more testing and can identify situations where you can always change IP or can never change IP.

    Thanks,
    Stuart Smith
    Administration Lead
    Web Age Solutions
    www.webagesolutions.com

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