kubernetes get open ports per pod

k8s_open_ports_in_a_pod.md

#!/bin/bash
# Find out how many mongo connections does a deployment creates

# define variables
export PATH=$PATH:/usr/local/bin
CONTEXT="$1"
DEPLOYMENT="$2"
CONNECTIONS_COUNTER=0
REQUESTED_PORT=27017

# switch kubectl context
kubectl config set-context ${CONTEXT}
CURRENT_CONTEXT=$(kubectl config current-context | cut -d"_" -f2)

# create an array of pods for the requested deployment
read -a DEPLOYMENT_PODS <<< $(kubectl get pods | grep ${DEPLOYMENT} | cut -d" " -f1 | tr '\n' ' ')

# loop through the pods and exec to get the current amount of open ports to mongo
for pod in ${DEPLOYMENT_PODS[@]}; do 
	TOTAL_PER_POD=$(kubectl exec -it $pod -- grep -v "rem_address" /proc/net/tcp | awk 'function hextodec(str,ret,n,i,k,c){
    ret = 0
    n = length(str)
    for (i = 1; i <= n; i++) {
        c = tolower(substr(str, i, 1))
        k = index("123456789abcdef", c)
        ret = ret * 16 + k
    }
    return ret
} {x=hextodec(substr($3,index($3,":")-2,2)); for (i=5; i>0; i-=2) x = x"."hextodec(substr($3,i,2))}{print x":"hextodec(substr($3,index($3,":")+1,4))}' | grep ${REQUESTED_PORT} | wc -l)
	((CONNECTIONS_COUNTER=CONNECTIONS_COUNTER+TOTAL_PER_POD))
done

echo "`date +%T-%d-%m-%y` - ${#DEPLOYMENT_PODS[@]} ${DEPLOYMENT} pods in ${CURRENT_CONTEXT} have ${CONNECTIONS_COUNTER} open connections to mongo" >> ${CURRENT_CONTEXT}_${DEPLOYMENT}.log