[slurm-users] [External] Fwd: Slurm MySQL database configuration

[Michael Robbert]

Peter,
I believe that the answer to your database question is that you don't have two MySQL/MariaDB servers running at the same time. The only way that I know of to run MySQL/MariaDB in an active-active setup, which is what you appear to be describing, is with replication. The other setup is to run it in an active-passive setup using something like Pacemaker/Corosync to manage which node is active at any one time.  The slurmctld and slurmdbd have built in mechanisms to do failover internally, but MySQL/MariaDB doesn't work that way.

Mike Robbert
Colorado School of Mines

On 7/23/20, 09:56, "slurm-users on behalf of Peter Mayes" <slurm-users-bounces at lists.schedmd.com on behalf of pmayes at lenovo.com> wrote:

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    Hi Folks,

    Thanks for responses.

    I probably didn't make my initial point totally clear, so following up
    with clarification.

    The NFS server is considered to be sufficiently highly available
    ("Designed for 99.9999% availability with redundant hot-swap components,
    including controllers and I/O modules, power supplies, cooling modules")
    that we had assumed this was sufficient for the Slurm database, without
    additional Database HA features, like Galera, DRBD, etc etc

    So the idea was to have the two Slurm server nodes, each running
    slurmctld, slurmdbd, mariadb, but the two mariadb instances would be
    referencing the same physical database, with only one of the Slurm nodes
    doing any database updates at any one time.

    Is this a possible configuration? If so, how to get both the mariadb
    instances to be running simultaneously (with one idle) accessing the
    same database files.

    It seems silly to have two database instances on the same NFS server
    replicating with something like Galera.

    Thanks again
    --
    Peter

    -------
    Hi,

    My first post to the list, so apologies if this is a FAQ,

    My configuration has two nodes allocated for Slurm masters, with a
    highly-available NFS server mounting a filesystem across the two nodes.

    I need advice on the best configuration.

    I naively thought of having a single MariaDB database located in the NFS
    server, with slurmctld, slurmdbd and mariadb running on both slurm
    nodes, with only one slurmdbd/mariadb actively touching the database at
    any one time.

    slurm.conf
    ----------
    SlurmctldHost=slurm1(a.b.c.1)
    SlurmctldHost=slurm2(a.b.c.2)

    AccountingStorageHost=slurm1
    AccountingStorageBackupHost=slurm2

    slurmdbd.conf
    -------------

    DbdHost=slurm1
    DbdBackupHost=slurm2

    StorageHost=localhost

    But MariaDB doesn't seem to like (possibly understandably) two mysql
    daemons accessing a single database instance from two servers.

    What would be the best way to configure this setup?

    Thanks in advance

    -- Peter
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