When you're running containers with Kubernetes, you often find that they pile up. This is by design. It's one of the advantages of containers: they're cheap to start whenever a new one is needed. You can use a front-end like OpenShift or OKD to manage pods and containers. Those make it easy to visualize what you have set up, and have a rich set of commands for quick interactions.
If a platform to manage containers doesn't fit your requirements, though, you can also get that information using only a Kubernetes toolchain, but there are a lot of commands you need for a full overview of a complex environment. For that reason, I wrote KRAWL, a simple script that scans pods and containers under the namespaces on Kubernetes clusters and displays the output of events, if any are found. It can also be used as Kubernetes plugin for the same purpose. It's a quick and easy way to get a lot of useful information.
Prerequisites
- You must have kubectl installed.
- Your cluster's kubeconfig must be either in its default location ($HOME/.kube/config) or exported (KUBECONFIG=/path/to/kubeconfig).
Usage
$ ./krawl
The script
#!/bin/bash
# AUTHOR: Abhishek Tamrakar
# EMAIL: abhishek.tamrakar08@gmail.com
# LICENSE: Copyright (C) 2018 Abhishek Tamrakar
#
# 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.
##
#define the variables
KUBE_LOC=~/.kube/config
#define variables
KUBECTL=$(which kubectl)
GET=$(which egrep)
AWK=$(which awk)
red=$(tput setaf 1)
normal=$(tput sgr0)
# define functions
# wrapper for printing info messages
info()
{
printf '\n\e[34m%s\e[m: %s\n' "INFO" "$@"
}
# cleanup when all done
cleanup()
{
rm -f results.csv
}
# just check if the command we are about to call is available
checkcmd()
{
#check if command exists
local cmd=$1
if [ -z "${!cmd}" ]
then
printf '\n\e[31m%s\e[m: %s\n' "ERROR" "check if $1 is installed !!!"
exit 1
fi
}
get_namespaces()
{
#get namespaces
namespaces=( \
$($KUBECTL get namespaces --ignore-not-found=true | \
$AWK '/Active/ {print $1}' \
ORS=" ") \
)
#exit if namespaces are not found
if [ ${#namespaces[@]} -eq 0 ]
then
printf '\n\e[31m%s\e[m: %s\n' "ERROR" "No namespaces found!!"
exit 1
fi
}
#get events for pods in errored state
get_pod_events()
{
printf '\n'
if [ ${#ERRORED[@]} -ne 0 ]
then
info "${#ERRORED[@]} errored pods found."
for CULPRIT in ${ERRORED[@]}
do
info "POD: $CULPRIT"
info
$KUBECTL get events \
--field-selector=involvedObject.name=$CULPRIT \
-ocustom-columns=LASTSEEN:.lastTimestamp,REASON:.reason,MESSAGE:.message \
--all-namespaces \
--ignore-not-found=true
done
else
info "0 pods with errored events found."
fi
}
#define the logic
get_pod_errors()
{
printf "%s %s %s\n" "NAMESPACE,POD_NAME,CONTAINER_NAME,ERRORS" > results.csv
printf "%s %s %s\n" "---------,--------,--------------,------" >> results.csv
for NAMESPACE in ${namespaces[@]}
do
while IFS=' ' read -r POD CONTAINERS
do
for CONTAINER in ${CONTAINERS//,/ }
do
COUNT=$($KUBECTL logs --since=1h --tail=20 $POD -c $CONTAINER -n $NAMESPACE 2>/dev/null| \
$GET -c '^error|Error|ERROR|Warn|WARN')
if [ $COUNT -gt 0 ]
then
STATE=("${STATE[@]}" "$NAMESPACE,$POD,$CONTAINER,$COUNT")
else
#catch pods in errored state
ERRORED=($($KUBECTL get pods -n $NAMESPACE --no-headers=true | \
awk '!/Running/ {print $1}' ORS=" ") \
)
fi
done
done< <($KUBECTL get pods -n $NAMESPACE --ignore-not-found=true -o=custom-columns=NAME:.metadata.name,CONTAINERS:.spec.containers[*].name --no-headers=true)
done
printf "%s\n" ${STATE[@]:-None} >> results.csv
STATE=()
}
#define usage for seprate run
usage()
{
cat << EOF
USAGE: "${0##*/} </path/to/kube-config>(optional)"
This program is a free software under the terms of Apache 2.0 License.
COPYRIGHT (C) 2018 Abhishek Tamrakar
EOF
exit 0
}
#check if basic commands are found
trap cleanup EXIT
checkcmd KUBECTL
#
#set the ground
if [ $# -lt 1 ]; then
if [ ! -e ${KUBE_LOC} -a ! -s ${KUBE_LOC} ]
then
info "A readable kube config location is required!!"
usage
fi
elif [ $# -eq 1 ]
then
export KUBECONFIG=$1
elif [ $# -gt 1 ]
then
usage
fi
#play
get_namespaces
get_pod_errors
printf '\n%40s\n' 'KRAWL'
printf '%s\n' '---------------------------------------------------------------------------------'
printf '%s\n' ' Krawl is a command line utility to scan pods and prints name of errored pods '
printf '%s\n\n' ' +and containers within. To use it as kubernetes plugin, please check their page '
printf '%s\n' '================================================================================='
cat results.csv | sed 's/,/,|/g'| column -s ',' -t
get_pod_events
This was originally published as the README in KRAWL's GitHub repository and is reused with permission.
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