Skip to content

Instantly share code, notes, and snippets.

@Bessonov
Created December 29, 2018 20:00
Show Gist options
  • Star 0 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save Bessonov/4b315e15252fa295df5c298542ed2c03 to your computer and use it in GitHub Desktop.
Save Bessonov/4b315e15252fa295df5c298542ed2c03 to your computer and use it in GitHub Desktop.
CockroachDB on Kubernetes (old example)
# copy of
# https://raw.githubusercontent.com/a-robinson/cockroach/k8s-tutorial/cloud/kubernetes/cockroachdb-statefulset.yaml
apiVersion: v1
kind: Service
metadata:
# This service is meant to be used by clients of the database. It exposes a ClusterIP that will
# automatically load balance connections to the different database pods.
name: cockroachdb-public
labels:
app: cockroachdb
spec:
ports:
# The main port, served by gRPC, serves Postgres-flavor SQL, internode
# traffic and the cli.
- port: 26257
targetPort: 26257
name: grpc
# The secondary port serves the UI as well as health and debug endpoints.
- port: 8080
targetPort: 8080
name: http
selector:
app: cockroachdb
---
apiVersion: v1
kind: Service
metadata:
# This service only exists to create DNS entries for each pod in the stateful
# set such that they can resolve each other's IP addresses. It does not
# create a load-balanced ClusterIP and should not be used directly by clients
# in most circumstances.
name: cockroachdb
labels:
app: cockroachdb
annotations:
# This is needed to make the peer-finder work properly and to help avoid
# edge cases where instance 0 comes up after losing its data and needs to
# decide whether it should create a new cluster or try to join an existing
# one. If it creates a new cluster when it should have joined an existing
# one, we'd end up with two separate clusters listening at the same service
# endpoint, which would be very bad.
service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
# Enable automatic monitoring of all instances when Prometheus is running in the cluster.
prometheus.io/scrape: "true"
prometheus.io/path: "_status/vars"
prometheus.io/port: "8080"
spec:
ports:
- port: 26257
targetPort: 26257
name: grpc
- port: 8080
targetPort: 8080
name: http
clusterIP: None
selector:
app: cockroachdb
---
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
name: cockroachdb-budget
labels:
app: cockroachdb
spec:
selector:
matchLabels:
app: cockroachdb
minAvailable: 67%
---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: cockroachdb
spec:
serviceName: "cockroachdb"
replicas: 3
template:
metadata:
labels:
app: cockroachdb
annotations:
scheduler.alpha.kubernetes.io/affinity: >
{
"podAntiAffinity": {
"preferredDuringSchedulingIgnoredDuringExecution": [{
"weight": 100,
"labelSelector": {
"matchExpressions": [{
"key": "app",
"operator": "In",
"values": ["cockroachdb"]
}]
},
"topologyKey": "kubernetes.io/hostname"
}]
}
}
# Init containers are run only once in the lifetime of a pod, before
# it's started up for the first time. It has to exit successfully
# before the pod's main containers are allowed to start.
# This particular init container does a DNS lookup for other pods in
# the set to help determine whether or not a cluster already exists.
# If any other pods exist, it creates a file in the cockroach-data
# directory to pass that information along to the primary container that
# has to decide what command-line flags to use when starting CockroachDB.
# This only matters when a pod's persistent volume is empty - if it has
# data from a previous execution, that data will always be used.
#
# If your Kubernetes cluster uses a custom DNS domain, you will have
# to add an additional arg to this pod: "-domain=<your-custom-domain>"
pod.alpha.kubernetes.io/init-containers: '[
{
"name": "bootstrap",
"image": "cockroachdb/cockroach-k8s-init:0.2",
"imagePullPolicy": "IfNotPresent",
"args": [
"-on-start=/on-start.sh",
"-service=cockroachdb"
],
"env": [
{
"name": "POD_NAMESPACE",
"valueFrom": {
"fieldRef": {
"apiVersion": "v1",
"fieldPath": "metadata.namespace"
}
}
}
],
"volumeMounts": [
{
"name": "datadir",
"mountPath": "/cockroach/cockroach-data"
}
]
}
]'
spec:
containers:
- name: cockroachdb
image: cockroachdb/cockroach:v1.0
imagePullPolicy: IfNotPresent
ports:
- containerPort: 26257
name: grpc
- containerPort: 8080
name: http
volumeMounts:
- name: datadir
mountPath: /cockroach/cockroach-data
command:
- "/bin/bash"
- "-ecx"
- |
# The use of qualified `hostname -f` is crucial:
# Other nodes aren't able to look up the unqualified hostname.
CRARGS=("start" "--logtostderr" "--insecure" "--host" "$(hostname -f)" "--http-host" "0.0.0.0")
# We only want to initialize a new cluster (by omitting the join flag)
# if we're sure that we're the first node (i.e. index 0) and that
# there aren't any other nodes running as part of the cluster that
# this is supposed to be a part of (which indicates that a cluster
# already exists and we should make sure not to create a new one).
# It's fine to run without --join on a restart if there aren't any
# other nodes.
if [ ! "$(hostname)" == "cockroachdb-0" ] || \
[ -e "/cockroach/cockroach-data/cluster_exists_marker" ]
then
# We don't join cockroachdb in order to avoid a node attempting
# to join itself, which currently doesn't work
# (https://github.com/cockroachdb/cockroach/issues/9625).
CRARGS+=("--join" "cockroachdb-public")
fi
exec /cockroach/cockroach ${CRARGS[*]}
# No pre-stop hook is required, a SIGTERM plus some time is all that's
# needed for graceful shutdown of a node.
terminationGracePeriodSeconds: 15
volumes:
- name: datadir
persistentVolumeClaim:
claimName: datadir
volumeClaimTemplates:
- metadata:
name: datadir
annotations:
volume.alpha.kubernetes.io/storage-class: anything
spec:
accessModes:
- "ReadWriteOnce"
resources:
requests:
storage: 1Gi
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment