Executando um cluster MariaDB Galera sem ferramentas de orquestração - Gerenciamento de contêiner de banco de dados:parte dois

Desligamento normal

$ docker kill -s 15 {db_container_name}

$ cat /containers/mariadb2/datadir/grastate.dat
# GALERA saved state
version: 2.1
uuid:    e70b7437-645f-11e8-9f44-5b204e58220b
seqno:   7099
safe_to_bootstrap: 1

Detectando o nó mais avançado

2016-11-07 01:49:19 5572 [ERROR] WSREP: It may not be safe to bootstrap the cluster from this node.
It was not the last one to leave the cluster and may not contain all the updates.
To force cluster bootstrap with this node, edit the grastate.dat file manually and set safe_to_bootstrap to 1 .

$ docker run --rm --name mariadb-recover \
        --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
        --volume /containers/mariadb1/datadir:/var/lib/mysql \
        --volume /containers/mariadb1/conf.d:/etc/mysql/conf.d \
        mariadb:10.2.15 \
        --wsrep_recover \
        --wsrep_cluster_address=gcomm://
2018-06-12  4:46:35 139993094592384 [Note] mysqld (mysqld 10.2.15-MariaDB-10.2.15+maria~jessie) starting as process 1 ...
2018-06-12  4:46:35 139993094592384 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
...
2018-06-12  4:46:35 139993094592384 [Note] Plugin 'FEEDBACK' is disabled.
2018-06-12  4:46:35 139993094592384 [Note] Server socket created on IP: '::'.
2018-06-12  4:46:35 139993094592384 [Note] WSREP: Recovered position: e70b7437-645f-11e8-9f44-5b204e58220b:7099

$ vim /containers/mariadb3/datadir/grasate.dat
...
safe_to_bootstrap: 1

Reinicializando o cluster

$ docker start mariadb0 # on host1

$ docker run -d \
        --name mariadb0 \
        --hostname mariadb0.weave.local \
        --net weave \
        --publish "3306" \
        --publish "4444" \
        --publish "4567" \
        --publish "4568" \
        $(weave dns-args) \
        --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
        --volume /containers/mariadb2/datadir:/var/lib/mysql \
        --volume /containers/mariadb2/conf.d:/etc/mysql/mariadb.conf.d \
        mariadb:10.2.15 \
        --wsrep_cluster_address=gcomm:// \
        --wsrep_sst_auth="root:PM7%[email protected]^1" \
        --wsrep_node_address=mariadb0.weave.local

• --env MYSQL_USER=proxysql
• --env MYSQL_PASSWORD=proxysqlpassword

$ docker start mariadb1 # on host1
$ docker start mariadb3 # on host3
$ docker stop mariadb0 # on host2
$ docker start mariadb2 # on host2

Controle de recursos

$ docker kill -s 15 mariadb1
$ docker rm -f mariadb1
$ docker run -d \
        --name mariadb1 \
        --hostname mariadb1.weave.local \
        --net weave \
        --publish "3306:3306" \
        --publish "4444" \
        --publish "4567" \
        --publish "4568" \
        $(weave dns-args) \
        --memory 16g \
        --memory-swap 16g \
        --ulimit nofile:16000:16000 \
        --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
        --volume /containers/mariadb1/datadir:/var/lib/mysql \
        --volume /containers/mariadb1/conf.d:/etc/mysql/mariadb.conf.d \
        mariadb:10.2.15 \
        --wsrep_cluster_address=gcomm://mariadb0.weave.local,mariadb1.weave.local,mariadb2.weave.local,mariadb3.weave.local \
        --wsrep_sst_auth="root:PM7%[email protected]^1" \
        --wsrep_node_address=mariadb1.weave.local

$ docker update \
    --memory 32g \
    --memory-swap 32g \
    mariadb1

Gerenciamento de configuração

$ vim /containers/mariadb3/conf.d/my.cnf

$ docker restart mariadb3

Backup

$ docker exec -it mariadb2 mysqldump -uroot -p --single-transaction > /backups/mariadb2/dump.sql

$ docker run --rm -it \
    -v /containers/mariadb2/datadir:/var/lib/mysql \
    -v /tmp/backup:/xtrabackup_backupfiles \
    perconalab/percona-xtrabackup \
    --backup --host=mariadb2 --user=root --password=mypassword

$ docker exec -it mariadb2 mysql -uroot -p -e 'SET GLOBAL innodb_fast_shutdown = 0'
$ docker kill -s 15 mariadb2
$ cp -Rf /containers/mariadb2/datadir /backups/mariadb2/datadir_copied
$ docker start mariadb2

Restaurar

$ docker exec -it mariadb2 mysql -uroot -p < /backups/mariadb2/dump.sql

$ mysql -uroot -p -h127.0.0.1 -P3306 < /backups/mariadb2/dump.sql

$ docker run --rm -it \
    -v mysql-datadir:/var/lib/mysql \
    -v /tmp/backup:/xtrabackup_backupfiles \
    perconalab/percona-xtrabackup \
    --prepare --target-dir /xtrabackup_backupfiles

$ docker run -d \
    --name mariadb-restored \
    --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
    -v /tmp/backup:/var/lib/mysql \
    mariadb:10.2.15

$ mkdir -p /containers/mariadb-restored/datadir
$ cp -Rf /backups/mariadb2/datadir_copied /containers/mariadb-restored/datadir
$ docker run -d \
    --name mariadb-restored \
    --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
    -v /containers/mariadb-restored/datadir:/var/lib/mysql \
    mariadb:10.2.15

Atualização da versão do banco de dados

0. 
   Faça backup do banco de dados. Não importa o backup físico ou lógico, mas o último usando mysqldump é recomendado.
   
1. 
   Faça o download da imagem mais recente para a qual gostaríamos de atualizar:
   

   $ docker pull mariadb:10.2.15

2. 
   Defina innodb_fast_shutdown como 0 para nosso contêiner de banco de dados:
   

   $ docker exec -it mariadb3 mysql -uroot -p -e 'SET GLOBAL innodb_fast_shutdown = 0'

3. 
   Graceful encerre o contêiner de banco de dados:
   

   $ docker kill --signal=TERM mariadb3

4. 
   Crie um novo contêiner com a nova imagem para nosso contêiner de banco de dados. Mantenha o restante dos parâmetros intactos, exceto usando o novo nome do contêiner (caso contrário, entraria em conflito):
   

   $ docker run -d \
           --name mariadb3-new \
           --hostname mariadb3.weave.local \
           --net weave \
           --publish "3306:3306" \
           --publish "4444" \
           --publish "4567" \
           --publish "4568" \
           $(weave dns-args) \
           --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
           --volume /containers/mariadb3/datadir:/var/lib/mysql \
           --volume /containers/mariadb3/conf.d:/etc/mysql/mariadb.conf.d \
           mariadb:10.2.15 \
           --wsrep_cluster_address=gcomm://mariadb0.weave.local,mariadb1.weave.local,mariadb2.weave.local,mariadb3.weave.local \
           --wsrep_sst_auth="root:PM7%[email protected]^1" \
           --wsrep_node_address=mariadb3.weave.local

5. 
   Execute o script mysql_upgrade:
   

   $ docker exec -it mariadb3-new mysql_upgrade -uroot -p

6. 
   Se nenhum erro ocorreu, remova o contêiner antigo, mariadb3 (o novo é mariadb3-new):
   

   $ docker rm -f mariadb3

7. 
   Caso contrário, se o processo de atualização falhar no meio, podemos voltar ao contêiner anterior:
   

   $ docker stop mariadb3-new
   $ docker start mariadb3

Failover

• Status wsrep_local_state_comment está sincronizado (O estado "Dessincronizado/Doador" também é possível, somente se wsrep_sst_method é xtrabackup, xtrabackup-v2 ou mariabackup).
• Status wsrep_cluster_status é Primário.

Escalando para fora

$ docker run -d \
        --name mariadb4 \
        --hostname mariadb4.weave.local \
        --net weave \
        --publish "3306:3307" \
        --publish "4444" \
        --publish "4567" \
        --publish "4568" \
        $(weave dns-args) \
        --env MYSQL_ROOT_PASSWORD="PM7%[email protected]^1" \
        --volume /containers/mariadb4/datadir:/var/lib/mysql \
        --volume /containers/mariadb3/conf.d:/etc/mysql/mariadb.conf.d \
        mariadb:10.2.15 \
        --wsrep_cluster_address=gcomm://mariadb1.weave.local,mariadb2.weave.local,mariadb3.weave.local,mariadb4.weave.local \
        --wsrep_sst_auth="root:PM7%[email protected]^1" \
        --wsrep_node_address=mariadb4.weave.local

$ docker exec -it proxysql1 mysql -uadmin -padmin -P6032
mysql> INSERT INTO mysql_servers(hostgroup_id,hostname,port) VALUES (10,'mariadb4.weave.local',3306);
mysql> INSERT INTO mysql_servers(hostgroup_id,hostname,port) VALUES (20,'mariadb4.weave.local',3306);
mysql> LOAD MYSQL SERVERS TO RUNTIME;
mysql> SAVE MYSQL SERVERS TO DISK;

$ vim /containers/proxysql1/proxysql.cnf # host1
$ vim /containers/proxysql2/proxysql.cnf # host2

mysql_servers =
(
        { address="mariadb1.weave.local" , port=3306 , hostgroup=10, max_connections=100 },
        { address="mariadb2.weave.local" , port=3306 , hostgroup=10, max_connections=100 },
        { address="mariadb3.weave.local" , port=3306 , hostgroup=10, max_connections=100 },
        { address="mariadb4.weave.local" , port=3306 , hostgroup=10, max_connections=100 },
        { address="mariadb1.weave.local" , port=3306 , hostgroup=20, max_connections=100 },
        { address="mariadb2.weave.local" , port=3306 , hostgroup=20, max_connections=100 },
        { address="mariadb3.weave.local" , port=3306 , hostgroup=20, max_connections=100 },
        { address="mariadb4.weave.local" , port=3306 , hostgroup=20, max_connections=100 }
)

Diminuição

$ docker kill -s 15 mariadb4
$ docker rm -f mariadb4

$ docker exec -it proxysql1 mysql -uadmin -padmin -P6032
mysql> DELETE FROM mysql_servers WHERE hostname="mariadb4.weave.local";
mysql> LOAD MYSQL SERVERS TO RUNTIME;
mysql> SAVE MYSQL SERVERS TO DISK;

Resumo