| author | title | summary | tags | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
Stephan Lichtenauer, Bretton Vine, Michael Gmelin |
MariaDB (Galera Cluster) |
MariaDB-Galera is a database cluster derived from (and largely compatible with) MySQL. |
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This is a flavour containing the mariadb database server with galera clustering solution enabled. It is currently WIP development image and separate from the mariadb image on purpose.
It is assumed that a persistent directory containing the mysql datadir is mounted in to /var/db/mysql, optionally you could copy in your server.cnf configuration if you do have specific needs not covered by the default configuration (see Installation chapter below).
Also, it supports parameters to regularly dump the content of the database into a SQL-file so you can create consistent backups from outside the jail.
To ensure that software and database file versions match, mysql_upgrade is run on startup. That way, you should be able to upgrade your mariadb installation by simply replacing the jail with a newer version as long as the database files are stored outside and mounted in (see above and examples below).
- Create a ZFS data set on the parent system beforehand
zfs create -o mountpoint=/mnt/mysqldata zroot/mysqldata - Create your local jail from the image or the flavour files.
- Clone the local jail
- Mount in the ZFS data set you created
pot mount-in -p <jailname> -m /var/db/mysql -d /mnt/mysqldata - Optionally export the ports after creating the jail:
pot export-ports -p <jailname> -e 3306:3306 -e 4567:4567 -e 4568:4568 -e 4444:4444 -e 4567:4567 -e 9104:9104 - Adjust to your environment:
sudo pot set-env -p <jailname> \ -E DATACENTER=<datacentername> \ -E NODENAME=<nodename> \ -E IP=<IP address of this system> \ -E CONSULSERVERS="<comma-deliminated list of consul server IP addresses>" \ -E GOSSIPKEY="<32 byte Base64 key from consul keygen>" \ -E DBROOTPASS=<database root password> \ -E DBSCRAPEPASS=<mysqld exporter user password> \ -E SERVERID=<unique identifier 1,2,3> \ -E GALERACLUSTER=<comma-deliminated list of all mariadb servers in cluster> \ [ -E GALERAPRIMARY=<Y> ] \ [ -E DUMPSCHEDULE="<cronschedule>" -E DUMPUSER=<backupuser> -E DUMPFILE=</insidejail/dumpfile.sql> ] \ [ -E LOADBALANCER=<IP address of haproxy-sql image> ] \ [ -E REMOTELOG=<IP address of syslog-ng server> ]
DATACENTER defines a common datacenter.
NODENAME defines the name of this node.
IP is the IP address which will be used to access services.
CONSULSERVERS is a comma-deliminated list of consul server instances. Do not include spaces!
e.g. CONSULSERVERS="10.0.0.2" or CONSULSERVERS="10.0.0.2,10.0.0.3,10.0.0.4,10.0.0.6,10.0.0.6"
GOSSIPKEY is the gossip encryption key for consul agent and must be passed in as a parameter.
DBROOTPASS is the root password for the mysql database, which must be passed in even if database exists and configured.
DBSCRAPEPASS is the password for the mysqld_exporter exporter user.
SERVERID is a unique identifier. Set to 1 for first server, 2 for second and so on.
GALERACLUSTER is a comma-deliminated list of all mariadb servers in the cluster.
GALERAPRIMARY is set on the first server in the cluster. You'll launch this node first. Do not set on the others.
DUMPSCHEDULE is a cron schedule is in the scheduling format of crontab, e.g. "*/5 * * * *". (include quotes)
DUMPUSER defaults to root and DUMPFILE defaults to /var/db/mysql/full_mariadb_backup.sql if you set a DUMPSCHEDULE but do not specify one or both of these parameters.
LOADBALANCER is the IP address of a haproxy-sql instance which will provide loadbalancing between two or three mariadb instances. A user called haproxy is created with no password and no access to databases.
REMOTELOG is the IP address of a destination syslog-ng server, such as with the loki flavour, or beast-of-argh flavour.
You can connect to the database server with a mariadb client.
Replication should be automatic between nodes once a database is added to first server.
You can use a loadbalancing/failover TCP proxy such as the haproxy-sql pot image to query all servers in the cluster. Make sure to set the LOADBALANCER variable to the IP of the haproxy-sql image in advance.