notes about k8s pdb
Let's say we have the following pdb and deployment
httpbin.yaml
# Copyright Istio Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
##################################################################################################
# httpbin service
##################################################################################################
apiVersion: v1
kind: ServiceAccount
metadata:
name: httpbin
---
apiVersion: v1
kind: Service
metadata:
name: httpbin
labels:
app: httpbin
service: httpbin
spec:
ports:
- name: http
port: 8000
targetPort: 80
selector:
app: httpbin
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: httpbin
spec:
replicas: 1
selector:
matchLabels:
app: httpbin
version: v1
template:
metadata:
labels:
app: httpbin
version: v1
spec:
serviceAccountName: httpbin
containers:
- image: docker.io/kennethreitz/httpbin
imagePullPolicy: IfNotPresent
name: httpbin
ports:
- containerPort: 80
pdb.yaml
apiVersion: policy/v1
kind: PodDisruptionBudget
metadata:
name: httpbin-pdb
spec:
selector:
matchLabels:
app: httpbin
maxUnavailable: 1
unhealthyPodEvictionPolicy: AlwaysAllow
Do you need to match for pdb to work?
A single matching label is sufficient, you don't have to match all.
How do you know if the pdb gets apply?
Do a kubectl describe pdb -n your-namespace
If there's no matching label that ties to a deployment, your event will have a message that says "no matching pod" found.
Also your status would have a total of 1 - meaning that it found a matching deployment/pods. For example, in the screenshot below, the current: 1 - shows that it gets applied and matched to a pod.
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