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This script runs health checks in a set of hosts and updates their status on an nginx server. It also sends email notifications with the linux mail command. All other dependencies come natively with linux. It is a great alternative to the comercial nginx health_heck feature.
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| #!/bin/bash | |
| # By @jacmkno - Activisual S.A.S. - http://activisual.net | |
| # Script summary | |
| # This script runs health cehcks in a set of hosts and updates their status on an nginx server | |
| HOSTS=(201.208.65.152 46.56.115.234 42.79.216.211) | |
| HOSTS_COUNT=3 # Number of hosts in the array | |
| MAIL_SUBJECT='ACTIVISUAL - Health check status change' | |
| MAIL_TO='webmaster@website.net' | |
| NGINX_CONF=nginx.conf | |
| #Expression used in grep to accept a proper response. Server response is stripped from linebreaks and the response headers are included at the begining | |
| TEST_EXPRESSION='HTTP/1.1 200 OK.*region-footer' | |
| SCRIPT_CRONSECS=120 # Calculate repetitions to take this ammount of time. Should equal your crontab setup. | |
| CURL_TIMEOUT=2 # Maximum time culr will wait for an answer | |
| EXTRA_SECS=2 # Wait this number of seconds after each prove | |
| MAX_ERRORS=3 # Flag server as down if the last MAX_ERRORS tests are all errors | |
| PROTOCOL='http' # All servers will be tested with HTTP protocol on port 80 | |
| let REPEAT="SCRIPT_CRONSECS/((CURL_TIMEOUT+EXTRA_SECS)*HOSTS_COUNT) - 1" | |
| last_lines=`tail -n 100 /tmp/healthchecks` | |
| echo $last_lines > /tmp/healthchecks | |
| for i in `seq $REPEAT`; do | |
| for host in "${HOSTS[@]}" | |
| do | |
| ans=`curl -is -m $CURL_TIMEOUT "$PROTOCOL://$host"|tr -d "\n"|grep -e "$TEST_EXPRESSION"|wc -l` | |
| echo $host:$ans >> /tmp/healthchecks | |
| errorsCnt=`grep "$host" /tmp/healthchecks|tail -n $MAX_ERRORS|grep ":0"|wc -l` | |
| let serverDown=errorsCnt/MAX_ERRORS | |
| oldStatus=`cat /tmp/health.$host` | |
| status="$host is down? $serverDown" | |
| if [ -n "$oldStatus" ] | |
| then | |
| if [ "$oldStatus" != "$status" ] | |
| then | |
| if [ "$serverDown" -eq 0 ] && [ "$errorsCnt" -gt 0 ]; then | |
| status="$oldStatus" | |
| else | |
| if [ "$serverDown" -eq 0 ] | |
| then | |
| sed 's/'"$host"'\(:[0-9]\+ \| \)down /'$host'\1/' $NGINX_CONF > /tmp/health.newconf | |
| else | |
| sed '/down/! s/'"$host"'\(:[0-9]\+ \| \)/&down /' $NGINX_CONF > /tmp/health.newconf | |
| fi | |
| echo "status change: $status, errors: $errorsCnt" | mail -s "$MAIL_SUBJECT" $MAIL_TO | |
| echo "status change: $status, errors: $errorsCnt" | |
| mv /tmp/health.newconf $NGINX_CONF | |
| sudo service nginx restart | |
| fi | |
| fi | |
| fi | |
| echo "$status, errors: $errorsCnt" | |
| echo $status > /tmp/health.$host | |
| sleep $EXTRA_SECS | |
| done | |
| done |
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