Create a gist now

Instantly share code, notes, and snippets.

What would you like to do?
MySQL replication statefulset resource definitions
apiVersion: v1
kind: ConfigMap
metadata:
name: mysql
labels:
app: mysql
data:
master.cnf: |
# Apply this config only on the master.
[mysqld]
log-bin
slave.cnf: |
# Apply this config only on slaves.
[mysqld]
super-read-only
# Headless service for stable DNS entries of StatefulSet members.
apiVersion: v1
kind: Service
metadata:
name: mysql
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
clusterIP: None
selector:
app: mysql
---
# Client service for connecting to any MySQL instance for reads.
# For writes, you must instead connect to the master: mysql-0.mysql.
apiVersion: v1
kind: Service
metadata:
name: mysql-read
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
selector:
app: mysql
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: mysql
spec:
serviceName: mysql
replicas: 3
template:
metadata:
labels:
app: mysql
annotations:
pod.beta.kubernetes.io/init-containers: '[
{
"name": "init-mysql",
"image": "mysql:5.7",
"command": ["bash", "-c", "
set -ex\n
# Generate mysql server-id from pod ordinal index.\n
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1\n
ordinal=${BASH_REMATCH[1]}\n
echo [mysqld] > /mnt/conf.d/server-id.cnf\n
# Add an offset to avoid reserved server-id=0 value.\n
echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf\n
# Copy appropriate conf.d files from config-map to emptyDir.\n
if [[ $ordinal -eq 0 ]]; then\n
cp /mnt/config-map/master.cnf /mnt/conf.d/\n
else\n
cp /mnt/config-map/slave.cnf /mnt/conf.d/\n
fi\n
"],
"volumeMounts": [
{"name": "conf", "mountPath": "/mnt/conf.d"},
{"name": "config-map", "mountPath": "/mnt/config-map"}
]
},
{
"name": "clone-mysql",
"image": "gcr.io/google-samples/xtrabackup:1.0",
"command": ["bash", "-c", "
set -ex\n
# Skip the clone if data already exists.\n
[[ -d /var/lib/mysql/mysql ]] && exit 0\n
# Skip the clone on master (ordinal index 0).\n
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1\n
ordinal=${BASH_REMATCH[1]}\n
[[ $ordinal -eq 0 ]] && exit 0\n
# Clone data from previous peer.\n
ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql\n
# Prepare the backup.\n
xtrabackup --prepare --target-dir=/var/lib/mysql\n
"],
"volumeMounts": [
{"name": "data", "mountPath": "/var/lib/mysql", "subPath": "mysql"},
{"name": "conf", "mountPath": "/etc/mysql/conf.d"}
]
}
]'
spec:
containers:
- name: mysql
image: mysql:5.7
env:
- name: MYSQL_ALLOW_EMPTY_PASSWORD
value: "1"
ports:
- name: mysql
containerPort: 3306
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 1
memory: 1Gi
livenessProbe:
exec:
command: ["mysqladmin", "ping"]
initialDelaySeconds: 30
timeoutSeconds: 5
readinessProbe:
exec:
# Check we can execute queries over TCP (skip-networking is off).
command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
initialDelaySeconds: 5
timeoutSeconds: 1
- name: xtrabackup
image: gcr.io/google-samples/xtrabackup:1.0
ports:
- name: xtrabackup
containerPort: 3307
command:
- bash
- "-c"
- |
set -ex
cd /var/lib/mysql
# Determine binlog position of cloned data, if any.
if [[ -f xtrabackup_slave_info ]]; then
# XtraBackup already generated a partial "CHANGE MASTER TO" query
# because we're cloning from an existing slave.
mv xtrabackup_slave_info change_master_to.sql.in
# Ignore xtrabackup_binlog_info in this case (it's useless).
rm -f xtrabackup_binlog_info
elif [[ -f xtrabackup_binlog_info ]]; then
# We're cloning directly from master. Parse binlog position.
[[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
rm xtrabackup_binlog_info
echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
fi
# Check if we need to complete a clone by starting replication.
if [[ -f change_master_to.sql.in ]]; then
echo "Waiting for mysqld to be ready (accepting connections)"
until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done
echo "Initializing replication from clone position"
# In case of container restart, attempt this at-most-once.
mv change_master_to.sql.in change_master_to.sql.orig
mysql -h 127.0.0.1 <<EOF
$(<change_master_to.sql.orig),
MASTER_HOST='mysql-0.mysql',
MASTER_USER='root',
MASTER_PASSWORD='',
MASTER_CONNECT_RETRY=10;
START SLAVE;
EOF
fi
# Start a server to send backups when requested by peers.
exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c \
"xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root"
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 100m
memory: 100Mi
volumes:
- name: conf
emptyDir: {}
- name: config-map
configMap:
name: mysql
volumeClaimTemplates:
- metadata:
name: data
spec:
storageClassName: gluster
accessModes: ["ReadWriteOnce"]
resources:
requests:
storage: 250Mi
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment