SuperAPI AI Directory
Partner with us中文AI newsFavorites
Skillspackage-mysql-ha-green

package-mysql-ha-green

Data & analytics

View repository

Updated 10-16 02:38

About this skill

MySQL Group Replication

Read references/configuration.md before changing desired state or running a lifecycle command.

Safety

  • Keep secrets out of colors.yml; use ignored COLORS_PAR_* exports.
  • Never set COLORS_PAR_PROFILE and never edit generated .colors/ files.
  • Default to build and create --dry-run; a real create or delete needs explicit authorization.
  • Keep compute-prevent-destroy: true. Lift it for one authorized delete with COLORS_PAR_COMPUTE_PREVENT_DESTROY=false.
  • Restrict mysql-ssh-sources and mysql-client-sources; do not use 0.0.0.0/0. The MySQL port is a public port.
  • The design needs exactly two database credentials. Do not introduce a third.

Commands

./green build              # render the work directory only
./green create --dry-run   # walk the graph, contact nothing
./green create             # converge, then snapshot, verify a restore, and assert
./green health             # read-only assertions against the live cluster
./green delete             # guarded teardown

A real lifecycle run needs Babashka, OpenTofu, Ansible and SSH; the shipped devenv.nix supplies them. build and --dry-run need none of that and no credential at all.

What it provisions

Three identical machines on a private network, one application-assigned reserved IP, firewall rules, and Cloudflare records. On the members: MySQL 8.0 in single-primary Group Replication, plus six systemd units — the endpoint claimer, the heartbeat, the binary-log archiver, its uploader, the snapshot job, and the verified restore.

Compute, SSH keys, and remote state are supplied by the pinned colors-compute library. Select a provider supported by that revision and configure its options and credentials. The package supplies three peer nodes and application network requirements; the library joins observed node addresses and SSH users for Ansible.

Use provider-backend: r2 or s3. R2 requires COLORS_PAR_R2_ACCESS_KEY_ID and COLORS_PAR_R2_SECRET_ACCESS_KEY; S3 uses the ambient AWS credential chain. The library owns managed profile keys, or uses configured external keys with ssh-private-key-path. Existing monolithic compute state requires explicit migration and is refused by this lifecycle.

This package also requires the library capability for an application-assigned reserved IP. The library supplies the endpoint agent; MySQL decides when a member is eligible to claim the address.

How failover works

Group Replication elects the new primary. Separately, a ten-second timer on each member claims the reserved IP when that member is ONLINE, PRIMARY and not super_read_only. The Cloudflare record's content is the reserved IP and never changes, so OpenTofu keeps owning DNS while the cluster owns the assignment.

The library creates the reserved IP without a node assignment. MySQL retains assignment ownership across failovers and subsequent infrastructure converges.

Backups and recovery

snapshot/ holds a daily GTID-stamped mysqldump; binlog/<member>/ holds continuously archived binary logs from every member; restore-check/ holds the verdict of the daily restore that is actually performed.

Recovery is: load the snapshot (it sets GTID_PURGED), then pipe the archived logs through mysql. Replay is idempotent by GTID and needs no position arithmetic. Full procedure in the repository README.

Bootstrapping is the dangerous operation

The cluster playbook bootstraps a group only after every member has reported it can see no ONLINE member anywhere. A member that bootstraps beside a live group forms a second group of one and the two diverge silently. Do not weaken that condition.