在Kubernetes中运行复制的MongoDB 4.2:未收到replset配置 [英] Running replicated MongoDB 4.2 in Kubernetes: replset config not being received
问题描述
我正在AWS上运行Kubernetes集群,需要配置复制的MongoDB 4.2数据库. 我正在使用StatefulSets,以便其他Pod(例如REST API NodeJS Pod)轻松连接到mongo实例(例如dsn:"mongodb://mongo-0.mongo,mongo-1.mongo,mongo-2. mongo:27017/app).
I'm running a Kubernetes cluster on AWS and need to configure a replicated MongoDB 4.2 Database. I'm using StatefulSets in order for other Pods (e.g., REST API NodeJS Pod) to easily connect to the mongo instances (example dsn: "mongodb://mongo-0.mongo,mongo-1.mongo,mongo-2.mongo:27017/app").
mongo-configmap.yaml(提供了一个shell脚本,可在创建mongo容器时执行复制初始化):
mongo-configmap.yaml (provides a shell script to perform the replication initialization upon mongo container creation):
apiVersion: v1
kind: ConfigMap
metadata:
name: mongo-init
data:
init.sh: |
#!/bin/bash
# wait for the readiness health check to pass
until ping -c 1 ${HOSTNAME}.mongo; do
echo "waiting for DNS (${HOSTNAME}.mongo)..."
sleep 2
done
until /usr/bin/mongo --eval 'printjson(db.serverStatus())'; do
echo "connecting to local mongo..."
sleep 2
done
echo "connected to local."
HOST=mongo-0.mongo:27017
until /usr/bin/mongo --host=${HOST} --eval 'printjson(db.serverStatus())'; do
echo "connecting to remote mongo..."
sleep 2
done
echo "connected to remote."
if [[ "${HOSTNAME}" != 'mongo-0' ]]; then
until /usr/bin/mongo --host=${HOST} --eval="printjson(rs.status())" \
| grep -v "no replset config has been received"; do
echo "waiting for replication set initialization"
sleep 2
done
echo "adding self to mongo-0"
/usr/bin/mongo --host=${HOST} --eval="printjson(rs.add('${HOSTNAME}.mongo'))"
fi
if [[ "${HOSTNAME}" == 'mongo-0' ]]; then
echo "initializing replica set"
/usr/bin/mongo --eval="printjson(rs.initiate(\
{'_id': 'rs0', 'members': [{'_id': 0, \
'host': 'mongo-0.mongo:27017'}]}))"
fi
echo "initialized"
while true; do
sleep 3600
done
mongo-service.yaml:
mongo-service.yaml:
apiVersion: v1
kind: Service
metadata:
name: mongo
labels:
app: mongo
spec:
clusterIP: None
ports:
- port: 27017
selector:
app: mongo
mongo-statefulset.yaml(一个Pod内有2个容器,一个用于实际DB,另一个用于初始化复制):
mongo-statefulset.yaml (2 containers inside one Pod, 1 for the actual DB, the other for initialization of the replication):
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: mongo
labels:
app: mongo
spec:
selector:
matchLabels:
app: mongo
serviceName: "mongo"
replicas: 3
template:
metadata:
labels:
app: mongo
spec:
terminationGracePeriodSeconds: 10
containers:
- name: mongodb
image: mongo:4.2
command:
- mongod
args:
- --replSet
- rs0
- "--bind_ip_all"
ports:
- containerPort: 27017
name: web
volumeMounts:
- name: database
mountPath: /data/db
livenessProbe:
exec:
command:
- /usr/bin/mongo
- --eval
- db.serverStatus()
initialDelaySeconds: 10
timeoutSeconds: 10
- name: init-mongo
image: mongo:4.2
command:
- bash
- /config/init.sh
volumeMounts:
- name: config
mountPath: /config
volumes:
- name: config
configMap:
name: "mongo-init"
volumeClaimTemplates:
- metadata:
name: database
annotations:
volume.beta.kubernetes.io/storage-class: mongodb-storage
spec:
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 5Gi
应用这些配置后,三个mongo pod会开始运行(mongo-0,mongo-1,mongo-2). 但是,其他吊舱无法连接到这些mongo吊舱. 进一步查看mongo-0 Pod(应该是主实例)后,发现复制无效.
After applying these configurations, the 3 mongo pods start running (mongo-0, mongo-1, mongo-2). However, other pods can't connect to these mongo pods. Further look into the mongo-0 pods (should be primary instance) reveals that the replication did not work.
kubectl exec -it mongo-0-/bin/bash
kubectl exec -it mongo-0 -- /bin/bash
然后运行"mongo"以启动mongo shell,并在mongo shell中输入"rs.status()"将得到以下输出:
Then running 'mongo' to start the mongo shell, and entering 'rs.status()' into the mongo shell results in the following output:
{
"info" : "run rs.initiate(...) if not yet done for the set",
"ok" : 0,
"errmsg" : "no replset config has been received",
"code" : 94,
"codeName" : "NotYetInitialized"
}
推荐答案
显然,mongo-4.x映像未安装"ping",因此,脚本的其余部分未执行. 将这两行添加到mongo-configmap.yaml中的脚本可解决此问题:
Apparently, mongo-4.x images do not come with 'ping' installed, therefore, the rest of the script was not executed. Adding these two lines to the script in mongo-configmap.yaml fixes the problem:
apt-get update
apt-get install iputils-ping --yes
这篇关于在Kubernetes中运行复制的MongoDB 4.2:未收到replset配置的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!