ClickHouse Uninstall and Cleanup

clickhouse_ansible already contains the official cleanup playbook: playbooks/uninstall_cluster.yml. It is suitable for environment recycling after the drill is completed, and for clearing the site before repeated reinstallation.

1. Scope of application

Uninstall the source cluster: inventory/hosts.deploy.ini
Uninstall the disaster recovery cluster: inventory/hosts.dr_deploy.ini

Requirements:

dbbot_inventory_purpose=deploy for inventory
Manual confirmation is required by default

2. Standard commands

Uninstall the source cluster:

cd /usr/local/dbbot/clickhouse_ansible/playbooks
ansible-playbook \
  -i ../inventory/hosts.deploy.ini \
  uninstall_cluster.yml

Uninstall the disaster recovery cluster:

cd /usr/local/dbbot/clickhouse_ansible/playbooks
ansible-playbook \
  -i ../inventory/hosts.dr_deploy.ini \
  uninstall_cluster.yml

3. What will be cleaned by default?

File: playbooks/vars/uninstall_config.yml

Enabled by default:

Stop and disable ClickHouse service
Delete ClickHouse configuration directory
Delete ClickHouse data directory
Delete ClickHouse log directory
Delete quick login configuration
Removed ClickHouse binary
Delete standalone ZooKeeper (if ZooKeeper is used in the current mode)

Off by default:

Uninstall /backup mount
Removed NFS client mount script

In other words, NFS client mounting traces will not be cleared by default to avoid accidentally deleting the shared backup disk.

4. Commonly used variables

Variable	Default value	Function
`uninstall_require_manual_confirm`	`true`	Whether to require confirmation before uninstalling
`uninstall_purge_clickhouse_config`	`true`	Whether to delete the configuration directory
`uninstall_purge_clickhouse_data`	`true`	Whether to delete the data directory
`uninstall_purge_clickhouse_logs`	`true`	Whether to delete the log directory
`uninstall_remove_clickhouse_binaries`	`true`	Whether to remove ClickHouse binaries
`uninstall_remove_backup_mount`	`false`	Whether to uninstall `/backup` and remove the mount script
`uninstall_purge_zookeeper`	`true`	Whether to clean up independent ZooKeeper

5. If you want to clean up the NFS client mount

cd /usr/local/dbbot/clickhouse_ansible/playbooks
ansible-playbook \
  -i ../inventory/hosts.deploy.ini \
  uninstall_cluster.yml \
  -e "uninstall_remove_backup_mount=true"

This will try:

Removed the mount entry in rc.local
Uninstall /backup
Delete mounting scripts and logs

6. Precautions

This is a high-risk cleanup action and requires manual input of a confirmation phrase by default.
If the target host has other business dependencies on /backup, do not directly turn on uninstall_remove_backup_mount=true.
If your goal is just to “reinstall ClickHouse”, there is usually no need to clean up the NFS server at the same time.