mk-alertmanagerconfigs.sh - Generates yaml for alertmanager namespaces in a cluster with provided kubeconfig (or default if none given)

mk-alertmanagerconfigs.sh

#!/bin/bash
# Replace Line 134 with the encoded webhook secret! and Lines 80 and 108 with your slack channel.
usage() {
 echo "Usage: $0 [OPTIONS]"
 echo "Options:"
 echo " -h,	Display this help message"
 echo " -a,	Combine all the configs into a single yaml 
		instead of breaking them up."
 echo " -v,	Enable verbose mode"
 echo " -c,	Insert the Clustername into the alertconfig"
 echo " -k, 	Specify path to the kubeconfig"
}


while getopts "hvac:k:" flag; do
 case $flag in
   h) # Handle the -h flag
   # Display script help information
   usage
   exit 0 
   ;;
   v) # Handle the -v flag
   # Enable verbose mode
   ;;
   a) # Handle the -a flag
   #combine all the configs into a single yaml instead of breaking them up.
   addative="true"
   ;;
   c) # Handle the -c flag with an argument
   clustername=$OPTARG
   # Specify the human readable clustername in the slack message. 
   ;;
   k) # Handle the -k with an argument
   kubeconfig=$OPTARG
   ;;
   \?)
   # Handle invalid options
   usage
   exit 1
   ;;
 esac
done

# Get all the namespaces
if [ -n "$kubeconfig" ]; then
  nsarray=$(kubectl get ns --no-headers --kubeconfig $kubeconfig |  awk '{print $1}')
else
  nsarray=$(kubectl get ns --no-headers  |  awk '{print $1}')
fi

# Adjust Clustername as the alertname or default to the upstream. 
#
if [ -n "$clustername" ]; then
  username="$clustername Alert"
else
  username='{{ template "slack.default.username" . }}'
fi

if [ -n "$addative" ]; then
  echo "" > alertmanagerConfigs.yaml
fi


for namespace in $nsarray
do
  config=$(cat <<-EOM
---
apiVersion: monitoring.coreos.com/v1alpha1
kind: AlertmanagerConfig
metadata:
  name: critical-alerts
  namespace: $namespace
spec:
  receivers:
    - name: slack
      slackConfigs:
        - apiURL:
            key: slack
            name: slack
          channel: '#YourChannelHere'
          username: $username
          sendResolved: true
          text: '{{ template "slack.rancher.text" . }}'
  route:
    groupBy:
      - job
    groupInterval: 2m
    groupWait: 30s
    matchers:
      - matchType: '=~'
        name: severity
        value: critical
    receiver: slack
    repeatInterval: 3h
---
apiVersion: monitoring.coreos.com/v1alpha1
kind: AlertmanagerConfig
metadata:
  name: general-alerts
  namespace: $namespace
spec:
  receivers:
    - name: slack
      slackConfigs:
        - apiURL:
            key: slack
            name: slack
          channel: '#YourChannelHere'
          color: '{{ if eq .Status "firing" }}warning{{ else }}good{{ end }}'
          username: $username
          sendResolved: true
          text: '{{ template "slack.rancher.text" . }}'
  route:
    groupBy:
      - job
    groupInterval: 2m
    groupWait: 30s
    matchers:
      - matchType: '=~'
        name: severity
        value: warning|critical
    receiver: slack
    repeatInterval: 3d
---
apiVersion: v1
kind: Secret
metadata:
  annotations:
    field.cattle.io/description: Slack URL to Slack instance
  name: slack
  namespace: $namespace
data:
  slack: >-
    <replace with encoded webhook> #FIXME Replace this line!
EOM
  )
  if [ -n "$addative" ]; then
    echo "$config" >> alertmanagerConfigs.yaml
  else
    echo "$config" > $namespace-alertmanagerConfig.yaml
  fi
done