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diff --git a/kubernetes/common/music/charts/zookeeper/README.md b/kubernetes/common/music/charts/zookeeper/README.md deleted file mode 100644 index 22bbac49dc..0000000000 --- a/kubernetes/common/music/charts/zookeeper/README.md +++ /dev/null @@ -1,140 +0,0 @@ -# incubator/zookeeper - -This helm chart provides an implementation of the ZooKeeper [StatefulSet](http://kubernetes.io/docs/concepts/abstractions/controllers/statefulsets/) found in Kubernetes Contrib [Zookeeper StatefulSet](https://github.com/kubernetes/contrib/tree/master/statefulsets/zookeeper). - -## Prerequisites -* Kubernetes 1.6+ -* PersistentVolume support on the underlying infrastructure -* A dynamic provisioner for the PersistentVolumes -* A familiarity with [Apache ZooKeeper 3.4.x](https://zookeeper.apache.org/doc/current/) - -## Chart Components -This chart will do the following: - -* Create a fixed size ZooKeeper ensemble using a [StatefulSet](http://kubernetes.io/docs/concepts/abstractions/controllers/statefulsets/). -* Create a [PodDisruptionBudget](https://kubernetes.io/docs/tasks/configure-pod-container/configure-pod-disruption-budget/) so kubectl drain will respect the Quorum size of the ensemble. -* Create a [Headless Service](https://kubernetes.io/docs/concepts/services-networking/service/) to control the domain of the ZooKeeper ensemble. -* Create a Service configured to connect to the available ZooKeeper instance on the configured client port. -* Optionally apply a [Pod Anti-Affinity](https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#inter-pod-affinity-and-anti-affinity-beta-feature) to spread the ZooKeeper ensemble across nodes. -* Optionally start JMX Exporter and Zookeeper Exporter containers inside Zookeeper pods. -* Optionally create a job which creates Zookeeper chroots (e.g. `/kafka1`). - -## Installing the Chart -You can install the chart with the release name `zookeeper` as below. - -```console -$ 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. - -### Installed Components -You can use `kubectl get` to view all of the installed components. - -```console{%raw} -$ 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 -``` - -1. `statefulsets/zookeeper` is the StatefulSet created by the chart. -1. `po/zookeeper-<0|1|2>` are the Pods created by the StatefulSet. Each Pod has a single container running a ZooKeeper server. -1. `svc/zookeeper-headless` is the Headless Service used to control the network domain of the ZooKeeper ensemble. -1. `svc/zookeeper` is a Service that can be used by clients to connect to an available ZooKeeper server. - -## Configuration -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, - -```console -$ helm install --name my-release -f values.yaml incubator/zookeeper -``` - -## Default Values - -- You can find all user-configurable settings, their defaults and commentary about them in [values.yaml](values.yaml). - -## Deep Dive - -## Image Details -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. - -## JVM Details -The Java Virtual Machine used for this chart is the OpenJDK JVM 8u111 JRE (headless). - -## ZooKeeper Details -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. - -## Failover -You can test failover by killing the leader. Insert a key: -```console -$ 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: -```console -$ 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: -```console -$ 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: -```console -$ 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 -``` - -## Scaling -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](https://zookeeper.apache.org/doc/r3.5.2-alpha/zookeeperReconfig.html) 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. - -## Limitations -* StatefulSet and PodDisruptionBudget are beta resources. -* Only supports storage options that have backends for persistent volume claims. |