Expand keepalived healthcheck to cover all critical components

CHANGELOG.md

@@ -16,13 +16,17 @@
 * CI workflow to build and push service images to GitHub Container Registry on master merge. (#97)
 * Pull-first with local build fallback for container images during deployment. (#97)
 
+### Fixed
+
+* Expand keepalived healthcheck to cover MySQL Router, Docker daemon, Superset service, and Redis. (#66)
+
 ### Changed
 
 * Completed [ARCHITECTURE.md](./docs/ARCHITECTURE.md) (#93)
 * Migrated CI from self-hosted to GitHub-hosted runners with Docker-in-Docker test infrastructure. (#94)
 * Test workflow always builds service images locally for reproducibility. (#97)
 
 ### Fixed
 
 * Fixed `run_mysql_server()` not instantiating `MySQLServer` class. (#94)
 * Disabled MD060 markdownlint rule to fix table column style false positives in documentation. (#94)

services/mysql-mgmt/docker_compose.yml

@@ -76,6 +76,8 @@ services:
           --execute="DROP USER 'superset'@'$(mysqlsh --python --execute "exec(open('/opt/interfaces.py').read())")';"
         ifmetric ${VIRTUAL_NETWORK_INTERFACE} 2
         /opt/envsubst-Linux-x86_64 < "/opt/keepalived.conf.tpl" > "/opt/default/keepalived.conf";
+        cp "/opt/healthcheck.sh" "/opt/default/healthcheck.sh";
+        chmod 755 "/opt/default/healthcheck.sh";
         chown --recursive superset:superset "/opt/default"
     cap_add:
       - "NET_ADMIN"

services/mysql-mgmt/healthcheck.sh

@@ -0,0 +1,10 @@
+#!/bin/bash
+set -euo pipefail
+
+killall -0 mysqlrouter 2>/dev/null || exit 1
+mysqladmin --login-path=superset --port=6446 ping 2>/dev/null || exit 1
+docker info > /dev/null 2>&1 || exit 1
+docker service inspect superset --format '{{.Spec.Name}}' 2>/dev/null | grep -q superset || exit 1
+docker exec redis redis-cli ping 2>/dev/null | grep -q PONG || exit 1
+
+exit 0

services/mysql-mgmt/keepalived.conf.tpl

@@ -6,9 +6,11 @@ global_defs {
 }
 
 vrrp_script status {
-    script "/bin/killall -0 mysqlrouter"
-    interval 1
-    weight 2
+    script "/opt/default/healthcheck.sh"
+    interval 5
+    weight -20
+    fall 3
+    rise 2
 }
 
 vrrp_instance virtual_instance {