Merge pull request #254 from dciabrin/galera-probe

Fix non-Primary checks in liveness probe

templates/galera/bin/mysql_probe.sh

@@ -1,27 +1,37 @@
 #!/bin/bash
-set -eu
+set -u
 
 # This secret is mounted by k8s and always up to date
 read -s -u 3 3< /var/lib/secrets/dbpassword MYSQL_PWD || true
 export MYSQL_PWD
 
 PROBE_USER=root
+function mysql_status_check {
+    local status=$1
+    local expect=$2
+    set -x
+    mysql -u${PROBE_USER} -sNEe "show status like '${status}';" | tail -1 | grep -w -e "${expect}"
+}
 
 # Consider the pod has "started" once mysql is reachable
+# and is part of the primary partition
 if [ "$1" = "startup" ]; then
-    mysql -u${PROBE_USER} -sNe "select(1);"
+    mysql_status_check wsrep_cluster_status Primary
     exit $?
 fi
 
-set -x
+# readiness and liveness probes are run by k8s only after start probe succeeded
 
 case "$1" in
     readiness)
         # If the node is e.g. a donor, it cannot serve traffic
-        mysql -u${PROBE_USER} -sNe "show status like 'wsrep_local_state_comment';" | grep -w -e Synced;;
+        mysql_status_check wsrep_local_state_comment Synced
+        ;;
     liveness)
-        # If the node is not in the primary partition, restart it
-        mysql -u${PROBE_USER} -sNe "show status like 'wsrep_cluster_status';" | grep -w -e Primary;;
+        # If the node is not in the primary partition, the failed liveness probe
+        # will make k8s restart this pod
+        mysql_status_check wsrep_cluster_status Primary
+        ;;
     *)
         echo "Invalid probe option '$1'"
         exit 1;;