This helm chart provides an implementation of the ZooKeeper StatefulSet found in Kubernetes Contrib Zookeeper StatefulSet.
This chart will do the following:
/kafka1).You can install the chart with the release name zookeeper as below.
$ helm repo add incubator http://storage.googleapis.com/kubernetes-charts-incubator $ helm install --name zookeeper incubator/zookeeper
If you do not specify a name, helm will select a name for you.
You can use kubectl get to view all of the installed components.
$ kubectl get all -l app=zookeeper NAME: zookeeper LAST DEPLOYED: Wed Apr 11 17:09:48 2018 NAMESPACE: default STATUS: DEPLOYED RESOURCES: ==> v1beta1/PodDisruptionBudget NAME MIN AVAILABLE MAX UNAVAILABLE ALLOWED DISRUPTIONS AGE zookeeper N/A 1 1 2m ==> v1/Service NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE zookeeper-headless ClusterIP None <none> 2181/TCP,3888/TCP,2888/TCP 2m zookeeper ClusterIP 10.98.179.165 <none> 2181/TCP 2m ==> v1beta1/StatefulSet NAME DESIRED CURRENT AGE zookeeper 3 3 2m
statefulsets/zookeeper is the StatefulSet created by the chart.po/zookeeper-<0|1|2> are the Pods created by the StatefulSet. Each Pod has a single container running a ZooKeeper server.svc/zookeeper-headless is the Headless Service used to control the network domain of the ZooKeeper ensemble.svc/zookeeper is a Service that can be used by clients to connect to an available ZooKeeper server.You can specify each parameter using the --set key=value[,key=value] argument to helm install.
Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,
$ helm install --name my-release -f values.yaml incubator/zookeeper
The image used for this chart is based on Ubuntu 16.04 LTS. This image is larger than Alpine or BusyBox, but it provides glibc, rather than ulibc or mucl, and a JVM release that is built against it. You can easily convert this chart to run against a smaller image with a JVM that is built against that image's libc. However, as far as we know, no Hadoop vendor supports, or has verified, ZooKeeper running on such a JVM.
The Java Virtual Machine used for this chart is the OpenJDK JVM 8u111 JRE (headless).
The ZooKeeper version is the latest stable version (3.4.10). The distribution is installed into /opt/zookeeper-3.4.10. This directory is symbolically linked to /opt/zookeeper. Symlinks are created to simulate a rpm installation into /usr.
You can test failover by killing the leader. Insert a key:
$ kubectl exec zookeeper-0 -- /opt/zookeeper/bin/zkCli.sh create /foo bar; $ kubectl exec zookeeper-2 -- /opt/zookeeper/bin/zkCli.sh get /foo;
Watch existing members:
$ kubectl run --attach bbox --image=busybox --restart=Never -- sh -c 'while true; do for i in 0 1 2; do echo zk-${i} $(echo stats | nc <pod-name>-${i}.<headless-service-name>:2181 | grep Mode); sleep 1; done; done'; zk-2 Mode: follower zk-0 Mode: follower zk-1 Mode: leader zk-2 Mode: follower
Delete Pods and wait for the StatefulSet controller to bring them back up:
$ kubectl delete po -l app=zookeeper $ kubectl get po --watch-only NAME READY STATUS RESTARTS AGE zookeeper-0 0/1 Running 0 35s zookeeper-0 1/1 Running 0 50s zookeeper-1 0/1 Pending 0 0s zookeeper-1 0/1 Pending 0 0s zookeeper-1 0/1 ContainerCreating 0 0s zookeeper-1 0/1 Running 0 19s zookeeper-1 1/1 Running 0 40s zookeeper-2 0/1 Pending 0 0s zookeeper-2 0/1 Pending 0 0s zookeeper-2 0/1 ContainerCreating 0 0s zookeeper-2 0/1 Running 0 19s zookeeper-2 1/1 Running 0 41s
Check the previously inserted key:
$ kubectl exec zookeeper-1 -- /opt/zookeeper/bin/zkCli.sh get /foo ionid = 0x354887858e80035, negotiated timeout = 30000 WATCHER:: WatchedEvent state:SyncConnected type:None path:null bar
ZooKeeper can not be safely scaled in versions prior to 3.5.x. This chart currently uses 3.4.x. There are manual procedures for scaling a 3.4.x ensemble, but as noted in the ZooKeeper 3.5.2 documentation these procedures require a rolling restart, are known to be error prone, and often result in a data loss.
While ZooKeeper 3.5.x does allow for dynamic ensemble reconfiguration (including scaling membership), the current status of the release is still alpha, and 3.5.x is therefore not recommended for production use.