I have written the below script to check whether my server running fine or not.But it is not properly working.It always showing Not runing even if it is running fine.Also the telnet in the script is not running working properly .Can any one help?
#!/bin/sh
export smtp=smtprelay.intra.xxx.com:25
Connect_redmine(){
telnet redmine.intra.xxx.com 443 <<EOF
exit 1;
EOF
}
Connect_redmine>/home/ssx00001/log_connect.txt
grep "Connected" /home/ssx00001/log_connect.txt
status=$?
if [ $status == 0 ]; then
echo `date` "Redmine PROD server is running fine"|mailx -r Redmine#xxx -s "Redmine PROD server is running" 777.p#xxx.com
else
echo "Redmine PROD server is not Running"|mailx -r redmine#xxx.com -s "Redmine PROD server is not running" 777.p#xxx.com
fi
A couple of questions first:
1] What does redmine do? Is it just a HTTPS server?
2] If [1] is true, can you do a wget of the index page, and use the result of that? It should be a lot easier to parse.
3] Telnetting into a HTTPS server, as far as I know, won't work, because it's not doing any of the handshaking that would be necessary for an SSL connection (which needs to occur before any content will be sent).
Using wget, you can do something like this:
wget https://redmine.intra.xxx.com/index.html
if [[-f "index.html" ] && [ -s "index.html" ]]
then
# The service is live
else
# Something is wrong
fi
Related
We are using linux Servers (CentOS) and one backup server
We only login to prod server if any there is any issue, else we check connection from backup server
We do no have any kind of monitoring tool
I have created a simple bash script on backup server as below
#!/bin/bash
date
cat /tmp/servers.txt | while read output
do
ping -c 1 "$output" > /dev/null
if [ $? -eq 0 ] ; then
echo "Server $output is UP"
else
echo "Server $output is Down"
fi
done
How do we get output of this script after log into this server automatically.
~/.bash_profile runs every time you log in, so that seems like the place you would want to put this code.
I have a Node.JS server running on PM2 that's crashing every once in a while because of a database limit, which I'm working on.
In the meantime, I thought I'd try just setting up a cron job in cpanel to restart the server every hour if it's down.
So I wrote a bash script like the following:
#!/bin/bash
status_code=$(curl --write-out %{http_code} --silent --output /dev/null https://website.com/)
date >> cronlog.txt
if [[ "$status_code" -ne 200 ]] ; then
pkill node
nohup pm2 start bin/www &
echo "Site status $status_code" >> cronlog.txt
echo "Restarting Server" >> cronlog.txt
exit
else
echo "Site fine" >> cronlog.txt
exit 0
fi
Running this from an SSH terminal works perfectly; if the site is down, it'll restart it.
However, once I set up the cron job in cpanel, like so: 0 * * * * /home/acc123/fix.sh, looking at the output of cronlog.txt, I see that the script is definitely running every hour, trying to restart the server - it's just that the server doesn't restart.
A preliminary Google suggested that maybe pm2 wasn't on the path that the cron job runs from, so I modified the script to look like this:
#!/bin/bash
status_code=$(curl --write-out %{http_code} --silent --output /dev/null https://website.com/)
date >> cronlog.txt
if [[ "$status_code" -ne 200 ]] ; then
pkill node
nohup /home/acc123/bin/pm2 start /home/acc123/bin/www &
echo "Site status $status_code" >> cronlog.txt
echo "Restarting Server" >> cronlog.txt
exit
else
echo "Site fine" >> cronlog.txt
exit 0
fi
But nothing changes. Looking at the text file I write to, the script is definitely running every hour, and it's definitely picking up that the site is down, but while the words "Restarting Server" get written to the text file, the server doesn't actually start.
Checking nohup.out confirms that nothing has been written to it, suggesting that somehow the command nohup /home/acc123/bin/pm2 start /home/acc123/bin/www & isn't running correctly.
I'm stumped. Has anyone seen something similar before?
Found it. Looks like node itself also wasn't on the path variable for the cron job. Explicitly specifying where node was fixed the problem.
I need some help with a Linux shell script which should automatically check if a host is reachable. It is best to ping port 22 every 3-5 seconds. If the port is reachable the program should execute the command service HelloWorld stop. If the host is not reachable, the script should automatically execute a command on the computer e.g. service HelloWorld start.
Does anyone know how to implement this?
I have something like this, but that not functionning,
#!/bin/bash
IP='192.168.1.1'
fping -c1 -t300 $IP 2>/dev/null 1>/dev/null
if [ "$?" = 0 ]
then
service helloworld stop
else
service helloworld start
fi
Try the following code
#!/bin/bash
IP='192.168.1.1'
PORT=22
(echo >/dev/tcp/$IP/$PORT) &>/dev/null
if [ "$?" = 0 ]
then
service helloworld stop
else
service helloworld start
fi
In this way, it's allowed to check IP with specific port is reachable or not
I want to use ping to check to see if a server is up. How would I do the following:
ping $URL
if [$? -eq 0]; then
echo "server live"
else
echo "server down"
fi
How would I accomplish the above? Also, how would I make it such that it returns 0 upon the first ping response, or returns an error if the first ten pings fail? Or, would there be a better way to accomplish what I am trying to do above?
I'ld recommend not to use only ping. It can check if a server is online in general but you can not check a specific service on that server.
Better use these alternatives:
curl
man curl
You can use curl and check the http_response for a webservice like this
check=$(curl -s -w "%{http_code}\n" -L "${HOST}${PORT}/" -o /dev/null)
if [[ $check == 200 || $check == 403 ]]
then
# Service is online
echo "Service is online"
exit 0
else
# Service is offline or not working correctly
echo "Service is offline or not working correctly"
exit 1
fi
where
HOST = [ip or dns-name of your host]
(optional )PORT = [optional a port; don't forget to start with :]
200 is the normal success http_response
403 is a redirect e.g. maybe to a login page so also accetable and most probably means the service runs correctly
-s Silent or quiet mode.
-L Defines the Location
-w In which format you want to display the response
-> %{http_code}\n we only want the http_code
-o the output file
-> /dev/null redirect any output to /dev/null so it isn't written to stdout or the check variable. Usually you would get the complete html source code before the http_response so you have to silence this, too.
nc
man nc
While curl to me seems the best option for Webservices since it is really checking if the service's webpage works correctly,
nc can be used to rapidly check only if a specific port on the target is reachable (and assume this also applies to the service).
Advantage here is the settable timeout of e.g. 1 second while curl might take a bit longer to fail, and of course you can check also services which are not a webpage like port 22 for SSH.
nc -4 -d -z -w 1 ${HOST} ${PORT} &> /dev/null
if [[ $? == 0 ]]
then
# Port is reached
echo "Service is online!"
exit 0
else
# Port is unreachable
echo "Service is offline!"
exit 1
fi
where
HOST = [ip or dns-name of your host]
PORT = [NOT optional the port]
-4 force IPv4 (or -6 for IPv6)
-d Do not attempt to read from stdin
-z Only listen, don't send data
-w timeout
If a connection and stdin are idle for more than timeout seconds, then the connection is silently closed. (In this case nc will exit 1 -> failure.)
(optional) -n If you only use an IP: Do not do any DNS or service lookups on any specified addresses, hostnames or ports.
&> /dev/null Don't print out any output of the command
You can use something like this -
serverResponse=`wget --server-response --max-redirect=0 ${URL} 2>&1`
if [[ $serverResponse == *"Connection refused"* ]]
then
echo "Unable to reach given URL"
exit 1
fi
Use the -c option with ping, it'll ping the URL only given number of times or until timeout
if ping -c 10 $URL; then
echo "server live"
else
echo "server down"
fi
Short form:
ping -c5 $SERVER || echo 'Server down'
Do you need it for some other script? Or are trying to hack some simple monitoring tool? In this case, you may want to take a look at Pingdom: https://www.pingdom.com/.
I using the following script function to check servers are online or not. It's useful when you want to check multiple servers. The function hide the ping output, and you can handle separately the server live or server down case.
#!/bin/bash
#retry count of ping request
RETRYCOUNT=1;
#pingServer: implement ping server functionality.
#Param1: server hostname to ping
function pingServer {
#echo Checking server: $1
ping -c $RETRYCOUNT $1 > /dev/null 2>&1
if [ $? -ne 0 ]
then
echo $1 down
else
echo $1 live
fi
}
#usage example, pinging some host
pingServer google.com
pingServer server1
One good solution is to use MRTG (a simple graphing tool for *NIX) with ping-probe script. look it up on Google.
read this for start.
Sample Graph:
In my code I have the following to run a remote script.
ssh root#host.domain.com "sh /home/user/backup_mysql.sh"
For some reason it keeps 255'ing on me. Any ideas?
I can SSH into the box just fine (passless keys setup)
REMOTE SCRIPT:
MUSER='root'
MPASS='123123'
MHOST="127.0.0.1"
VERBOSE=0
### Set bins path ###
GZIP=/bin/gzip
MYSQL=/usr/bin/mysql
MYSQLDUMP=/usr/bin/mysqldump
RM=/bin/rm
MKDIR=/bin/mkdir
MYSQLADMIN=/usr/bin/mysqladmin
GREP=/bin/grep
### Setup dump directory ###
BAKRSNROOT=/.snapshots/tmp
#####################################
### ----[ No Editing below ]------###
#####################################
### Default time format ###
TIME_FORMAT='%H_%M_%S%P'
### Make a backup ###
backup_mysql_rsnapshot(){
local DBS="$($MYSQL -u $MUSER -h $MHOST -p$MPASS -Bse 'show databases')"
local db="";
[ ! -d $BAKRSNROOT ] && ${MKDIR} -p $BAKRSNROOT
${RM} -f $BAKRSNROOT/* >/dev/null 2>&1
# [ $VERBOSE -eq 1 ] && echo "*** Dumping MySQL Database ***"
# [ $VERBOSE -eq 1 ] && echo -n "Database> "
for db in $DBS
do
local tTime=$(date +"${TIME_FORMAT}")
local FILE="${BAKRSNROOT}/${db}.${tTime}.gz"
# [ $VERBOSE -eq 1 ] && echo -n "$db.."
${MYSQLDUMP} --single-transaction -u ${MUSER} -h ${MHOST} -p${MPASS} $db | ${GZIP} -9 > $FILE
done
# [ $VERBOSE -eq 1 ] && echo ""
# [ $VERBOSE -eq 1 ] && echo "*** Backup done [ files wrote to $BAKRSNROOT] ***"
}
### Die on demand with message ###
die(){
echo "$#"
exit 999
}
### Make sure bins exists.. else die
verify_bins(){
[ ! -x $GZIP ] && die "File $GZIP does not exists. Make sure correct path is set in $0."
[ ! -x $MYSQL ] && die "File $MYSQL does not exists. Make sure correct path is set in $0."
[ ! -x $MYSQLDUMP ] && die "File $MYSQLDUMP does not exists. Make sure correct path is set in $0."
[ ! -x $RM ] && die "File $RM does not exists. Make sure correct path is set in $0."
[ ! -x $MKDIR ] && die "File $MKDIR does not exists. Make sure correct path is set in $0."
[ ! -x $MYSQLADMIN ] && die "File $MYSQLADMIN does not exists. Make sure correct path is set in $0."
[ ! -x $GREP ] && die "File $GREP does not exists. Make sure correct path is set in $0."
}
### Make sure we can connect to server ... else die
verify_mysql_connection(){
$MYSQLADMIN -u $MUSER -h $MHOST -p$MPASS ping | $GREP 'alive'>/dev/null
[ $? -eq 0 ] || die "Error: Cannot connect to MySQL Server. Make sure username and password are set correctly in $0"
}
### main ####
verify_bins
verify_mysql_connection
backup_mysql_rsnapshot
This is usually happens when the remote is down/unavailable; or the remote machine doesn't have ssh installed; or a firewall doesn't allow a connection to be established to the remote host.
ssh returns 255 when an error occurred or 255 is returned by the remote script:
EXIT STATUS
ssh exits with the exit status of the remote command or
with 255 if an error occurred.
Usually you would an error message something similar to:
ssh: connect to host host.domain.com port 22: No route to host
Or
ssh: connect to host HOSTNAME port 22: Connection refused
Check-list:
What happens if you run the ssh command directly from the command line?
Are you able to ping that machine?
Does the remote has ssh installed?
If installed, then is the ssh service running?
This error will also occur when using pdsh to hosts which are not contained in your "known_hosts" file.
I was able to correct this by SSH'ing into each host manually and accepting the question "Do you want to add this to known hosts".
If there's a problem with authentication or connection, such as not being able to read a password from the terminal, ssh will exit with 255 without being able to run your actual script. Verify to make sure you can run 'true' instead, to see if the ssh connection is established successfully.
Isn't the problem in the lines:
### Die on demand with message ###
die(){
echo "$#"
exit 999
}
Correct me if I'm wrong but I believe exit 999 is out of range for an exit code and results in a exit status of 255.
I was stumped by this. Once I got passed the 255 problem... I ended up with a mysterious error code 1. This is the foo to get that resolved:
pssh -x '-tt' -h HOSTFILELIST -P "sudo yum -y install glibc"
-P means write the output out as you go and is optional. But the -x '-tt' trick is what forces a psuedo tty to be allocated.
You can get a clue what the error code 1 means this if you try:
ssh AHOST "sudo yum -y install glibc"
You may see:
[slc#bastion-ci ~]$ ssh MYHOST "sudo yum -y install glibc"
sudo: sorry, you must have a tty to run sudo
[slc#bastion-ci ~]$ echo $?
1
Notice the return code for this is 1, which is what pssh is reporting to you.
I found this -x -tt trick here. Also note that turning on verbose mode (pssh --verbose) for these cases does nothing to help you.
It can very much be an ssh-agent issue.
Check whether there is an ssh-agent PID currently running with eval "$(ssh-agent -s)"
Check whether your identity is added with ssh-add -l and if not, add it with ssh-add <pathToYourRSAKey>.
Then try again your ssh command (or any other command that spawns ssh daemons, like autossh for example) that returned 255.
If above didn't help: check if locale is valid on client and server:
https://www.linuxbabe.com/linux-server/fix-ssh-locale-environment-variable-error
How do not pass locale through ssh
### Die on demand with message ###
die(){
echo "$#"
exit 999
}
I don't have the rep to comment on Alex's answer but the exit 999 line returns code 231 on my WSL Ubuntu 20.04.4 box. Not quite sure why that is returned but I understand that it's out of range.