I am searching for a way where i can inject env variable value to configmap so by defining LOG_SEVERITY as part of my deployment as env variable the value will be automatilcy injected to the configmap.
kind: ConfigMap
apiVersion: v1
data:
log.properties: |
timeout=10
severity=${LOG_SEVERITY}
You would have to use some kind of templating tool to process the YAML. Helm is popular (though that doesn't directly handle environment variables). For your case I would strongly recommend envsubst, it will handle this case nicely.
Like @coderanger mentioned you can use envsubst and Helm. I'll just provide tad more details and a another way ;)
envsubst
In your config_map.yml you would have:
severity= $LOG_SEVERITYThen just create new environmental variable and execute kubectl in a following way:
export LOG_SEVERITY="9"
envsubst < config_map.yml | kubectl apply -f -
Helm
Create a template and calling it.
kind: ConfigMap
apiVersion: v1
data:
log.properties: |
timeout=10
severity= {{ .Values.logSeverity }}
You would need to define a default value of severity inside mychart/values.yaml
logSeverity: 1And setting a different value by adding --set flag to the helm call.
helm install --set logSeverity=9 ./mychart
This is nicely explained inside Helm documentation The Chart Template Developer’s Guide. Keep in mind this is way more complicated to just use helm as a wrapper for Kubernetes files.
sed
sed -i 's/$LOG_SEVERITY/9/g' input.txt
I recommend reading How to use sed to find and replace text in files in Linux / Unix shell.