Web, Email & MySQL Database Cluster : server2 doesn't handle DNS

Discussion in 'General' started by electronico_nc, Aug 30, 2018.

  1. ahrasis

    ahrasis Well-Known Member

    I am not familiar with HAProxy so if suits you well, go for it. I will stay with the ISPConfig mirror dns server setup for a little while longer.

    I thought the referred tutorial (https://www.howtoforge.com/tutorial...abase-cluster-on-debian-8.4-with-ispconfig-3/) already covers database cluster from master server to slave server @till? Both dns server - server1 and server2 - should have the same database via this tutorial.

    Mirroring server2 to server1 following another tutorial (https://www.howtoforge.com/how-to-r...and-secondary-with-ispconfig-3-debian-squeeze) after the above should not affect the database cluster, right?
     
  2. Fact is that slave could not act anything without an online master.
    In a dual server setup I would imagine that server1 datas (master) could be replicated to server2 datas (master too) and being R/W by server(1||2)
     
  3. ahrasis

    ahrasis Well-Known Member

    It does in my setup following both tutorials I mentioned above; as what I have in server1, are also available in server2.

    In the event server1 is offline (which I tested by switching it off), server2 can still display websites replicated on it.

    The only thing I haven't tested yet is running ISPConfig control panel in server2.
     
  4. till

    till Super Moderator Staff Member ISPConfig Developer

    That's wrong, the slave is fully working when the master is down whcih @ahrasis pointed out already. The only thing that you can't do is to manage the node(s) when its management server is down, but that's the same with many other non-ispconfig HA setups as well, when the management node of a MySQL cluster is down, then the databases will keep working but you can not manage them until you put the management node online again. And as I explained oabve already, you can even make the ISPConfig management node HA by putting it's database into a database cluster instead of using a local database. But most people won't need that as it is uncritical when the management UI is down for maintenance a few minutes in several years when the actual services like mail, web, database, and DNS are not affected by this downtime.
     
  5. Thanks @till @ahrasis for your answers !
    After a lot of time, server1 is now online again (had to be completely erased and rebuilt), but unconfigured.
    I'm a bit confused about its ISPConfig configuration (especially about connecting Linux userId to webId)
    Should databases between servers be synced before re-installing ISPConfig on server1 ?
    Should unison be active before re-installing ISPConfig on server1 ?
    About websites, they have been copied to server1, but they are actually owned by unknown Linux userid (as ISPConfig is not yet installed), Will ISPConfig recreate the Linux userid from database ?
    Thanks again from your time.
     
  6. till

    till Super Moderator Staff Member ISPConfig Developer

    You mean you do not have a backup of your primary server that you restored?
     
  7. For shortcuts :
    I need to restore primary server from the secondary one.

    EDIT : I have backups for :
    /etc
    /usr/local/ispconfig
    others are on secondary server :
    /var/www
    /var/vmail
    databases
     
    Last edited: Sep 4, 2018
  8. I think to :
    - let's unison finish its resync
    - reconfigure MySQL master-master replication
    - restore
    • /etc/passwd
    • /etc/group
    • /etc/shadow
    • /etc/gshadow
    Install ISPConfig

    Does it seem OK ?
     
    Last edited: Sep 4, 2018
  9. till

    till Super Moderator Staff Member ISPConfig Developer

    That should be generally ok.
     
  10. Hello,

    I'm completely lost with this thing.
    I've been unable to re-install the master server (especially databases replication)

    The running slave is an old Ubuntu 14.04.5 running ISPConfig 3.0.5.4p9.
    A new cluster is being installed on 2 new servers : Ubuntu 18;04

    Supposing the latest ISPC 3.1 will be installed on the new cluster,
    Can ISPConfig Migration Toolkit be used to transfert evrything from the 'standalone' slave server to the new cluster ?
    Thanks again for your time.
     
  11. till

    till Super Moderator Staff Member ISPConfig Developer

    Puhh, that's not easy to predict, it might work but I haven't tested such a scenario, so I'm not sure if it will fully work.
     
    electronico_nc likes this.
  12. ahrasis

    ahrasis Well-Known Member

    I am not sure why you cannot restore your master when you have a backup. You simply have to build a perfect server, restore the backup directories and files, then the database, and update ISPConfig on the slave and master. It could be because your new master is using newer version of ISPConfig.

    I think to restore the master you shouldn't sync the database to the slave at first. Nor should you apply unison as yet. Make sure it is all working good before reconfiguring database sync and unison with the slave. The slave can always be rebuild if the master is working good.

    I am not sure about ISPConfig Migration Toolkit because I haven't used it for case like yours.
     

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