add helm v2 chart for patroni with petset (#57)

* feat(patroni): add helm v2 chart for patroni with petset

* chore(patroni): vendor etcd chart

* feat(patroni): have patroni use vendored etcd by default

* fix(patroni): use console instead of bash

* fix(patroni): make termination commands more reliable

* docs(patroni): add documentation to the configurable values

* docs(patroni): describe how to access postgres

* docs(patroni): add some details about how patroni on k8s works

* fix(patroni): do not require GCS by default

incubator/patroni/Chart.yaml

@@ -0,0 +1,12 @@
+name: patroni
+description: "Highly available elephant herd: HA PostgreSQL cluster."
+version: 0.1.0
+home: https://github.com/zalando/patroni
+sources:
+  - https://github.com/zalando/patroni
+  - https://github.com/zalando/spilo
+maintainers:
+  - name: Team ACID @ Zalando SE
+    email: team-acid@zalando.de
+  - name: Team Teapot @ Zalando SE
+    email: team-teapot@zalando.de

incubator/patroni/README.md

@@ -0,0 +1,117 @@
+# Patroni Helm Chart
+
+This directory contains a Kubernetes chart to deploy a five node patroni cluster using a petset.
+
+## Prerequisites Details
+* Kubernetes 1.3 with alpha APIs enable
+* PV support on the underlying infrastructure
+
+## PetSet Details
+* http://kubernetes.io/docs/user-guide/petset/
+
+## PetSet Caveats
+* http://kubernetes.io/docs/user-guide/petset/#alpha-limitations
+
+## Todo
+* Make namespace configurable
+
+## Chart Details
+This chart will do the following:
+
+* Implement a HA scalable PostgreSQL cluster using Kubernetes PetSets
+
+## Get this chart
+
+Download the latest release of the chart from the [releases](../../../releases) page.
+
+Alternatively, clone the repo if you wish to use the development snapshot:
+
+```console
+$ git clone https://github.com/kubernetes/charts.git
+```
+
+## Installing the Chart
+
+To install the chart with the release name `my-release`:
+
+```console
+$ helm install --name my-release patroni-x.x.x.tgz
+```
+
+## Connecting to Postgres
+
+Your access point is a cluster IP. In order to access it spin up another pod:
+
+```console
+$ kubectl run -i --tty ubuntu --image=ubuntu:16.04 --restart=Never -- bash -il
+```
+
+Then, from inside the pod, connect to postgres:
+
+```console
+$ apt-get update && apt-get install postgresql-client -y
+$ psql -U admin -h my-release-patroni.default.svc.cluster.local postgres
+<admin password from values.yaml>
+postgres=>
+```
+
+## Configuration
+
+The following tables lists the configurable parameters of the patroni chart and their default values.
+
+|       Parameter         |           Description               |                         Default                     |
+|-------------------------|-------------------------------------|-----------------------------------------------------|
+| `Name`                  | Service name                        | `patroni`                                           |
+| `Namespace`             | Service namespace                   | `default`                                           |
+| `Spilo.Image`           | Container image name                | `registry.opensource.zalan.do/acid/spilo-9.5`       |
+| `Spilo.Version`         | Container image tag                 | `1.0-p5`                                            |
+| `ImagePullPolicy`       | Container pull policy               | `IfNotPresent`                                      |
+| `Replicas`              | k8s petset replicas                 | `5`                                                 |
+| `Component`             | k8s selector key                    | `patroni`                                           |
+| `Resources.Cpu`         | container requested cpu             | `100m`                                              |
+| `Resources.Memory`      | container requested memory          | `512Mi`                                             |
+| `Resources.Storage`     | Persistent volume size              | `1Gi`                                               |
+| `Credentials.Superuser` | password for the superuser          | `tea`                                               |
+| `Credentials.Admin`     | password for the admin user         | `cola`                                              |
+| `Credentials.Standby`   | password for the replication user   | `pinacolada`                                        |
+| `Etcd.Discovery`        | domain name of etcd cluster         | `<release-name>-etcd.<namespace>.svc.cluster.local` |
+
+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 patroni-x.x.x.tgz
+```
+
+> **Tip**: You can use the default [values.yaml](values.yaml)
+
+## Cleanup
+
+In order to remove everything you created a simple `helm delete <release-name>` isn't enough (as of now), but you can do the following:
+
+```console
+$ release=<release-name>
+$ helm delete $release
+$ grace=$(kubectl get po $release-patroni-0 --template '{{.spec.terminationGracePeriodSeconds}}')
+$ kubectl delete petset,po -l release=$release
+$ sleep $grace
+$ kubectl delete pvc -l release=$release
+```
+
+## Internals
+
+Patroni is responsible for electing a Postgres master pod by leveraging etcd.
+It then exports this master via a Kubernetes service and a label query that filters for `spilo-role=master`.
+This label is dynamically set on the pod that acts as the master and removed from all other pods.
+Consequently, the service endpoint will point to the current master.
+
+```console
+$ kubectl get pods -l spilo-role -L spilo-role
+NAME                   READY     STATUS    RESTARTS   AGE       SPILO-ROLE
+my-release-patroni-0   1/1       Running   0          9m        replica
+my-release-patroni-1   1/1       Running   0          9m        master
+my-release-patroni-2   1/1       Running   0          8m        replica
+my-release-patroni-3   1/1       Running   0          8m        replica
+my-release-patroni-4   1/1       Running   0          8m        replica
+```

incubator/patroni/charts/etcd/.helmignore

@@ -0,0 +1,21 @@
+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj

incubator/patroni/charts/etcd/Chart.yaml

@@ -0,0 +1,9 @@
+name: etcd
+home: https://github.com/coreos/etcd
+version: 0.1.0
+description: Etcd Helm chart for Kubernetes.
+sources:
+  - https://github.com/coreos/etcd
+maintainers:
+  - name: Lachlan Evenson
+    email: lachlan@deis.com

incubator/patroni/charts/etcd/README.md

@@ -0,0 +1,178 @@
+# Etcd Helm Chart
+
+Credit to https://github.com/ingvagabund. This is an implementation of that work
+
+* https://github.com/kubernetes/contrib/pull/1295
+
+## Prerequisites Details
+* Kubernetes 1.3 with alpha APIs enable
+* PV support on the underlying infrastructure
+
+## PetSet Details
+* http://kubernetes.io/docs/user-guide/petset/
+
+## PetSet Caveats
+* http://kubernetes.io/docs/user-guide/petset/#alpha-limitations
+
+## Todo
+* Implement SSL
+
+## Chart Details
+This chart will do the following:
+
+* Implemented a dynamically scalable etcd cluster using Kubernetes PetSets
+
+## Get this chart
+
+Download the latest release of the chart from the [releases](../../../releases) page.
+
+Alternatively, clone the repo if you wish to use the development snapshot:
+
+```bash
+$ git clone https://github.com/kubernetes/charts.git
+```
+
+## Installing the Chart
+
+To install the chart with the release name `my-release`:
+
+```bash
+$ helm install --name my-release etcd-x.x.x.tgz
+```
+
+## Configuration
+
+The following tables lists the configurable parameters of the etcd chart and their default values.
+
+|       Parameter       |           Description            |                         Default                          |
+|-----------------------|----------------------------------|----------------------------------------------------------|
+| `Name`         | Spark master name                | `etcd`                                           |
+| `Image`        | Container image name             | `gcr.io/google_containers/etcd-amd64`                         |
+| `ImageTag`     | Container image tag              | `2.2.5`                                               |
+| `ImagePullPolicy`     | Container pull policy     | `Always`                                               |
+| `Replicas`     | k8s petset replicas          | `3`                                                      |
+| `Component`    | k8s selector key                 | `etcd`                                           |
+| `Cpu`          | container requested cpu          | `100m`                                                   |
+| `Memory`    |container requested memory                 | `512Mi`                                           |
+| `ClientPort`  | k8s service port                 | `2379`                                                   |
+| `PeerPorts`| Container listening port         | `2380`                                                   |
+| `Storage`| Persistent volume size         | `1Gi`                                                   |
+
+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,
+
+```bash
+$ helm install --name my-release -f values.yaml etcd-x.x.x.tgz
+```
+
+> **Tip**: You can use the default [values.yaml](values.yaml)
+
+# Deep dive
+
+## Cluster Health
+
+```
+$ for i in <0..n>; do kubectl exec <release-podname-$i> -- sh -c 'etcdctl cluster-health'; done
+```
+eg.
+```
+$ for i in {0..9}; do kubectl exec named-lynx-etcd-$i --namespace=etcd -- sh -c 'etcdctl cluster-health'; done
+member 7878c44dabe58db is healthy: got healthy result from http://named-lynx-etcd-7.named-lynx-etcd:2379
+member 19d2ab7b415341cc is healthy: got healthy result from http://named-lynx-etcd-4.named-lynx-etcd:2379
+member 6b627d1b92282322 is healthy: got healthy result from http://named-lynx-etcd-3.named-lynx-etcd:2379
+member 6bb377156d9e3fb3 is healthy: got healthy result from http://named-lynx-etcd-0.named-lynx-etcd:2379
+member 8ebbb00c312213d6 is healthy: got healthy result from http://named-lynx-etcd-8.named-lynx-etcd:2379
+member a32e3e8a520ff75f is healthy: got healthy result from http://named-lynx-etcd-5.named-lynx-etcd:2379
+member dc83003f0a226816 is healthy: got healthy result from http://named-lynx-etcd-2.named-lynx-etcd:2379
+member e3dc94686f60465d is healthy: got healthy result from http://named-lynx-etcd-6.named-lynx-etcd:2379
+member f5ee1ca177a88a58 is healthy: got healthy result from http://named-lynx-etcd-1.named-lynx-etcd:2379
+cluster is healthy
+```
+
+## Failover
+
+If any etcd member fails it gets re-joined eventually.
+You can test the scenario by killing process of one of the pets:
+
+```shell
+$ ps aux | grep etcd-1
+$ kill -9 ETCD_1_PID
+```
+
+```shell
+$ kubectl get pods -l "app=etcd"
+NAME                 READY     STATUS        RESTARTS   AGE
+etcd-0               1/1       Running       0          54s
+etcd-2               1/1       Running       0          51s
+```
+
+After a while:
+
+```shell
+$ kubectl get pods -l "app=etcd"
+NAME                 READY     STATUS    RESTARTS   AGE
+etcd-0               1/1       Running   0          1m
+etcd-1               1/1       Running   0          20s
+etcd-2               1/1       Running   0          1m
+```
+
+You can check state of re-joining from ``etcd-1``'s logs:
+
+```shell
+$ kubectl logs etcd-1
+Waiting for etcd-0.etcd to come up
+Waiting for etcd-1.etcd to come up
+ping: bad address 'etcd-1.etcd'
+Waiting for etcd-1.etcd to come up
+Waiting for etcd-2.etcd to come up
+Re-joining etcd member
+Updated member with ID 7fd61f3f79d97779 in cluster
+2016-06-20 11:04:14.962169 I | etcdmain: etcd Version: 2.2.5
+2016-06-20 11:04:14.962287 I | etcdmain: Git SHA: bc9ddf2
+...
+```
+
+## Scaling using kubectl
+
+This is for reference. Scaling should be managed by `helm upgrade`
+
+The etcd cluster can be scale up by running ``kubectl patch`` or ``kubectl edit``. For instance,
+
+```sh
+$ kubectl get pods -l "app=etcd"
+NAME      READY     STATUS    RESTARTS   AGE
+etcd-0    1/1       Running   0          7m
+etcd-1    1/1       Running   0          7m
+etcd-2    1/1       Running   0          6m
+
+$ kubectl patch petset/etcd -p '{"spec":{"replicas": 5}}'
+"etcd" patched
+
+$ kubectl get pods -l "app=etcd"
+NAME      READY     STATUS    RESTARTS   AGE
+etcd-0    1/1       Running   0          8m
+etcd-1    1/1       Running   0          8m
+etcd-2    1/1       Running   0          8m
+etcd-3    1/1       Running   0          4s
+etcd-4    1/1       Running   0          1s
+```
+
+Scaling-down is similar. For instance, changing the number of pets to ``4``:
+
+```sh
+$ kubectl edit petset/etcd
+petset "etcd" edited
+
+$ kubectl get pods -l "app=etcd"
+NAME      READY     STATUS    RESTARTS   AGE
+etcd-0    1/1       Running   0          8m
+etcd-1    1/1       Running   0          8m
+etcd-2    1/1       Running   0          8m
+etcd-3    1/1       Running   0          4s
+```
+
+Once a pet is terminated (either by running ``kubectl delete pod etcd-ID`` or scaling down),
+content of ``/var/run/etcd/`` directory is cleaned up.
+If any of the etcd pets restarts (e.g. caused by etcd failure or any other),
+the directory is kept untouched so the pet can recover from the failure.