Script to check Elasticsearch clusters for under-replicated indices

check-elasticsearch-underreplicated.sh

#!/bin/sh
#
# script accepts URLs of Elasticsearch clusters as arguments
# exit code table:
# 0 - no underreplicated indices
# 1 - found underreplicated indices
# 2 - unable to connect to one of those URLs could not be connected to
# 3 - timed out getting list of indices
#
for var in "$@"
do
  if curl --output /dev/null --max-time 1 --connect-timeout 1 --silent --head --fail "$var"
  then
    output=$(curl --silent --max-time 30 --connect-timeout 1 "$var/_cat/indices?h=rep,index")
    status=$?
    if [ $status -eq 0 ]
    then
      matches=$(echo "$output" | egrep "^0\s+")
      if [ ! -z "$matches" ]
      then
        echo "The following indices are underreplicated:"
        echo "$matches"
        exit 1
      fi
    else
      exit 3
    fi
  else
    exit 2
  fi
done

exit 0