09b3c6ca07
Kolla-ansible is currently installing mariadb cluster on hosts defined in group['mariadb'] and render haproxy configuration for this hosts. This is not enough if user want to have several service databases in several mariadb clusters (shards). Spread service databases to multiple clusters (shards) is usefull especially for databases with high load (neutron,nova). How it works ? It works exactly same as now, but group reference 'mariadb' is now used as group where all mariadb clusters (shards) are located, and mariadb clusters are installed to dynamic groups created by group_by and host variable 'mariadb_shard_id'. It also adding special user 'shard_X' which will be used for creating users and databases, but only if haproxy is not used as load-balance solution. This patch will not affect user which has all databases on same db cluster on hosts in group 'mariadb', host variable 'mariadb_shard_id' is set to 0 if not defined. Mariadb's task in loadbalancer.yml (haproxy) is configuring mariadb default shard hosts as haproxy backends. If mariadb role is used to install several clusters (shards), only default one is loadbalanced via haproxy. Mariadb's backup is working only for default shard (cluster) when using haproxy as mariadb loadbalancer, if proxysql is used, all shards are backuped. After this patch will be merged, there will be way for proxysql patches which will implement L7 SQL balancing based on users and schemas. Example of inventory: [mariadb] server1 server2 server3 mariadb_shard_id=1 server4 mariadb_shard_id=1 server5 mariadb_shard_id=2 server6 mariadb_shard_id=3 Extra: wait_for_loadbalancer is removed instead of modified as its role is served by check already. The relevant refactor is applied as well. Change-Id: I933067f22ecabc03247ea42baf04f19100dffd08 Co-Authored-By: Radosław Piliszek <radoslaw.piliszek@gmail.com>
17 lines
643 B
YAML
17 lines
643 B
YAML
---
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# Explicitly wait for the database to be accessible via the load balancer.
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# Sometimes it can reject connections even when all database services are up,
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# due to the health check polling in HAProxy.
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- name: Wait for MariaDB service to be ready through VIP
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become: true
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command: >
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docker exec {{ mariadb_service.container_name }}
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mysql -h {{ database_address }} -P {{ database_port }}
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-u {{ mariadb_shard_database_user }} -p{{ database_password }} -e 'show databases;'
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register: result
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until: result is success
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changed_when: False
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retries: 6
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delay: 10
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when: mariadb_shard_id == mariadb_default_database_shard_id
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