Using ssh inside a script to run another script that itself calls ssh - linux

I'm trying to write a script that builds a list of nodes then ssh into the first node of that list
and runs a checknodes.sh script which it's self is just a for i loop that calls checknode.sh
The first 2 lines seems to work ok, the list builds successfully, but then I get either get just the echo line of checknodes.sh to print out or an error saying cat: gpcnodes.txt: No such file or directory
MYSCRIPT.sh:
#gets the master node for the job
MASTERNODE=`qstat -t -u \* | grep $1 | awk '{print$8}' | cut -d'#' -f 2 | cut -d'.' -f 1 | sed -e 's/$/.com/' | head -n 1`
#builds list of nodes in job
ssh -qt $MASTERNODE "qstat -t -u \* | grep $1 | awk '{print$8}' | cut -d'#' -f 2 | cut -d'.' -f 1 | sed -e 's/$/.com/' > /users/issues/slow_job_starts/gpcnodes.txt"
ssh -qt $MASTERNODE cd /users/issues/slow_job_starts/
ssh -qt $MASTERNODE /users/issues/slow_job_starts/checknodes.sh
checknodes.sh
for i in `cat gpcnodes.txt `
do
echo "### $i ###"
ssh -qt $i /users/issues/slow_job_starts/checknode.sh
done
checknode.sh
str=`hostname`
cd /tmp
time perf record qhost >/dev/null 2>&1 | sed -e 's/^/${str}/'
perf report --pretty=raw | grep % | head -20 | grep -c kernel.kallsyms | sed -e "s/^/`hostname`:/"

When ssh -qt $MASTERNODE cd /users/issues/slow_job_starts/ is finished, the changed directory is lost.
With the backquotes replaced by $(..) (not an error here, but get used to it), the script would be something like
for i in $(cat /users/issues/slow_job_starts/gpcnodes.txt)
do
echo "### $i ###"
ssh -nqt $i /users/issues/slow_job_starts/checknode.sh
done
or better
while read -r i; do
echo "### $i ###"
ssh -nqt $i /users/issues/slow_job_starts/checknode.sh
done < /users/issues/slow_job_starts/gpcnodes.txt
Perhaps you would also like to change your last script (start with cd /users/issues/slow_job_starts)
You will find more problems, like sed -e 's/^/${str}/' (the ${str} inside single quotes won't be replaced by a host), but this should get you started.
EDIT:
I added option -n to the ssh call.
Redirects stdin from /dev/null (actually, prevents reading from stdin).
Without this option only one node is checked.

Related

echo text to multiple files in bash script

I am working on a bash script that uses pssh to run external commands, then join the output of the commands with the IP of each server. pssh has an option -o that writes a file for each server into a specified directory, but if the commands do not run, you just have an empty file. What I am having issues with is updating these empty files with something like "Server Unreachable" so that I know there was a connection issue reaching the server and to not cause problems with the rest of the script.
Here is what I have so far:
#!/bin/bash
file="/home/user/tools/test-host"
now=$(date +"%F")
folder="./cnxhwinfo-$now/"
empty="$(find ./cnxhwinfo-$now/ -maxdepth 1 -type f -name '*' -size 0 -printf '%f%2d')"
command="echo \$(uptime | awk -F'( |,|:)+' '{d=h=m=0; if (\$7==\"min\") m=\$6; else {if (\$7~/^day/) {d=\$6;h=\$8;m=\$9} else {h=\$6;m=\$7}}} {print d+0,\"days\",h+0,\"hours\",m+0,\"minutes\"}'), \$(hostname | awk '{print \$1}'), \$(sudo awk -F '=' 'FNR == 2 {print \$2}' /etc/connex-release/version.txt), \$(lscpu | awk -F: 'BEGIN{ORS=\", \";} NR==4 || NR==6 || NR==15 {print \$2}' | sed 's/ *//g') \$(free -k | awk '/Mem:/{print \$2}'), \$(df -Ph | awk '/var_lib/||/root/ {print \$2,\",\"\$5,\",\"}')"
pssh -h $file -l user -t 10 -i -o /home/user/tools/cnxhwinfo-$now -x -tt $command
echo "Server Unreachable" | tee "./cnxhwinfo-$now/$empty"
ls ./cnxhwinfo-$now >> ./cnx-data-$now
cat ./cnxhwinfo-$now/* >> ./cnx-list-$now
paste -d, ./cnx-data-$now ./cnx-list-$now >>./cnx-data-"$(date +"%F").csv"
I was trying to use find to locate the empty files and write "Server" unavailable using tee with this:
echo "Server Unreachable" | tee "./cnxhwinfo-$now/$empty"
if the folder specified doesn't already exist i get this error:
tee: ./cnxhwinfo-2019-09-03/: Is a directory
And if it does exist (ie, i run the script again), it instead creates a file named after the IP addresses returned by the find command, like this:
192.168.1.2 192.168.1.3 192.168.1.4 1
I've also tried:
echo "Server Unreachable" | tee <(./cnxhwinfo-$now/$empty)
The find command outputs the IP addresses on a single line with a space in between each one, so I thought that would be fine for tee to use, but I feel like I am either running into syntax issues, or am going about this the wrong way. I have another version of this same script that uses regular ssh and works great, just much slower than using pssh.
empty should be an array, assuming none of the file names will contain any whitespace in their names.
readarray -t empty < <(find ...)
echo "Server unreachable" | (cd ./cnxhwinfo-$now/; tee "${empty[#]}" > /dev/null)
Otherwise, you are building a single file name by concatenating the empty file names.

Testing active ssh keys on the local network

I am trying currently to achieve a bash script that will validate if SSH keys on a server are still linked to known hosts that are active on the local area network. You can find below the beginning of my bash script to achieve this:
#!/bin/bash
# LAN SSH KEYS DISCOVERY SCRIPT
# TRYING TO FIND THOSE SSH KEYS NOW
cat /etc/passwd | grep /bin/bash > bash_users
cat bash_users | cut -d ":" -f 6 > cutted.bash_users_home_dir
for bash_users in $(cat cutted.bash_users_home_dir)
do
ls -al $bash_users/.ssh/*id_* >> ssh-keys.txt
done
# DISCOVERING THE KNOWN_HOSTS NOW
for known_hosts in $(cat cutted.bash_users_home_dir)
do
cat $bash_users/.ssh/known_hosts | awk '{print $1}' | sort -u >>
hosts_known.txt
sleep 2
done
hosts_known=$(wc -l hosts_known.txt)
echo "We have $hosts_known known hosts that could be still active via SSH
keys"
# TIME TO TEST WHICH SSH servers are still active with the SSH keys
# AND THIS IS WHERE I AM FROZEN...
# Would love to have bash script that could
# ssh -l $users_that_have_/bin/bash -i $ssh_keys $ssh_servers
# Would also be very nice if it could save active
# SSH servers with the valid keys in output.txt in the format
# username:local-IP:/path/to/SSH_key
Please feel very comfortable to edit/modify the bash script above if it can serve better the goals described.
Any help would be very appreciated,
Thanks
The following works cool:
</etc/passwd \
grep /bin/bash |
cut -d: -f6 |
sudo xargs -i -- sh -c '
[ -e "$1" ] && cat "$1"
' -- {}/.ssh/known_hosts |
cut -d' ' -f1 |
tr ',' '\n' |
sed '
/^\[/{
s/\[\(.*\)\]:\(.*\)/\1 \2/;
t;
};
s/$/ 22/;
' |
sort -u |
xargs -l1 -- sh -c '
if echo "~" | nc -q1 -w3 "$1" "$2" | grep -q "^SSH"; then
echo "#### SUCCESS $1 $2";
else
echo "#### ERROR $1 $2";
fi
' --
So:
Start with /etc/passwd
Filter all "bash_users" as you call them
Filter user home directories only cut -d: -f6
For each user home directory sudo xargs -i -- run
Check if the file .ssh/known_hosts inside the user home directory exists
If it does, print it
Filter only hosts names
Multiple hosts signatures may share same key and are separated by a comma. Replace comma for newline
Now a sed script:
If a line starts with a [ that means it has a format of [host]:port and I want to replace it with host port
If the line does not start with a [ I add 22 to the end of the line so it's host 22
Then I sort -u
Now for each line:
I get the ssh version from ssh echo "~" | nc hostname port returns smth like "SSH-2.0-OpenSSH_6.0" + newline + "Protocol mismatch".
So if the line returned by nc hostname port starts with SSH that means there is ssh running on the other side
I added timeout for unresponsive hosts, but I think nc -w timeout option may also be used. Probably also nc -q 1 should be specified.
Now the real fun is, when you add the max-procs option to the last xargs line, you can check all hosts simultaneously. On my host I have 47 unique addresses and xargs -P30 checks them ALL in like 2 seconds.
But really there are some problems. The script needs root to read from all users known_hosts. But worse, the known_hosts may be hashed. It would be better to firstly know the list of hosts on your network, and then generate known_hosts from it. It would look like ssh-keyscan -f list_of_hosts > ~/.ssh/known_hosts or similar. Generaly ssh-keygen -F hostname should be used if a host exists in known_hosts, sadly there is no listing command. known_hosts file format may be found in ssh documentation.

bash script while loop

hi i am new in bash scripting.
This is my script in this i use while loop this is working till giving input to ping the ips in serverfile but further i want to use those ips to make files of each ip as below i am doing but it has some issue i think there must be more while loops in it . but its not working it takes only one ip as input and make the only one file and further adding in the required file its not working on whole input lets say there are 5 ips in the file it only make the first ip file.
#!/bin/bash
l2=$(tail -1 /root/serverfile | grep hadoop | tr ' ' '\n' | grep hadoop)
awk '{print $1}' < serverFile.txt | while read ip; do
if ping -c1 $ip >/dev/null 2>&1; then
cd /usr/local/nagios/etc/objects/Hadoop
cp Hadoop-node.cfg $l2.cfg
sed -i 's/192.168.0.1/'$ip'/' $l2.cfg
sed -i 's/Hadoop-node/'$l2'/' $l2.cfg
echo "cfg_file=/usr/local/nagios/etc/objects/Hadoop/$l2.cfg" >> /usr/local/nagios/etc/nagios.cfg
service nagios restart
echo " Node is added successfull"
echo $ip IS UP
else
echo $ip IS DOWN NOT PINGING
fi
done

Executing a string as a command in bash that contains pipes

I'm trying to list some ftp directories. I can't work out how to make bash execute a command that contains pipes correctly.
Here's my script:
#/bin/sh
declare -a dirs=("/dir1" "/dir2") # ... and lots more
for d in "${dirs[#]}"
do
cmd='echo "ls /mydir/'"$d"'/*.tar*" | sftp -b - -i ~/mykey user#example.com 2>&1 | tail -n1'
$cmd
done
This just outputs:
"ls /mydir/dir1/*.tar*" | sftp -b - -i ~/mykey user#example.com 2>&1 | tail -n1
"ls /mydir/dir2/*.tar*" | sftp -b - -i ~/mykey user#example.com 2>&1 | tail -n1
How can I make bash execute the whole string including the echo? I also need to be able to parse the output of the command.
I don't think that you need to be using the -b switch at all. It should be sufficient to specify the commands that you would like to execute as a string:
#/bin/bash
dirs=("/dir1" "/dir2")
for d in "${dirs[#]}"
do
printf -v d_str '%q' "$d"
sftp -i ~/mykey user#example.com "ls /mydir/$d_str/*.tar*" 2>&1 | tail -n1
done
As suggested in the comments (thanks #Charles), I've used printf with the %q format specifier to protect against characters in the directory name that may be interpreted by the shell.
First you need to use /bin/bash as shebang to use BASH arrays.
Then remove echo and use command substitution to capture the output:
#/bin/bash
declare -a dirs=("/dir1" "/dir2") # ... and lots more
for d in "${dirs[#]}"
do
output=$(ls /mydir/"$d"/*.tar* | sftp -b - -i ~/mykey user#example.com 2>&1 | tail -n1)
echo "$output"
done
I will however advise you not use ls's output in sftp command. You can replace that with:
output=$(echo "/mydir/$d/"*.tar* | sftp -b - -i ~/mykey user#example.com 2>&1 | tail -n1)
Don't store the command in a string; just use it directly.
#/bin/bash
declare -a dirs=("/dir1" "/dir2") # ... and lots more
for d in "${dirs[#]}"
do
echo "ls /mydir/$d/*.tar*" | sftp -b - -i ~/mykey user#example.com 2>&1 | tail -n1
done
Usually, people store the command in a string so they can both execute it and log it, as a misguided form of factoring. (I'm of the opinion that it's not worth the trouble required to do correctly.)
Note that sftp reads from standard input by default, so you can just use
echo "ls ..." | sftp -i ~/mykey user#example.com 2>&1 | tail -n1
You can also use a here document instead of a pipeline.
sftp -i ~/mykey user#example.com 2>&1 <<EOF | tail -n1
ls /mydir/$d/*.tar.*
EOF

Why part of the script cannot execute in the crontab

I have a script stopping the application and zipping some files:
/home/myname/project/stopWithZip.sh
With the properties below:
-rwxrwxr-x. 1 myname myname778 Jun 25 13:48 stopWithZip.sh
Here is the content of the script:
ps -ef | grep project | grep -v grep | awk '{print $2}' |xargs kill -15
month=`date +%m`
year=`date +%Y`
fixLogs=~/project/log/fix/$year$month/*.log.*
errorLogs=~/project/log/error/$year$month/log.*
for log in $fixLogs
do
if [ ! -f "$log.gz" ];
then
gzip $log
echo "Archived:"$log
else
echo "skipping" $log
fi
done
echo "Archived fix log files done"
for log in $errorLogs
do
if [ ! -f "$log.gz" ]; then
gzip $log
echo "Archived:"$log
else
echo "skipping" $log
fi
done
echo "Archived errorlog files done"
The problem is except this ps -ef | grep project | grep -v grep | awk '{print $2}' |xargs kill -15 command, other gzip commands are not executed. I totally don't understand why.
I cannot see any compression of the logs in the directory.
BTW, when I execute the stopWithZip.sh explicitly in command line, it works perfectly fine.
In crontab:
00 05 * * 2-6 /home/myname/project/stopWithZip.sh >> /home/myname/project/cronlog/$(date +"\%F")-stop.log 2>&1 (NOT work)
In command line:
/home/myname/project>./stopWithZip.sh (work)
Please help
The script fails when run under cron because your script is invoked with project in its path, so the kill pipeline kills the script too.
You could prove (or disprove) this by adding some tracing. Log the output of ps and of awk to log files:
ps -ef |
tee /tmp/ps.log.$$ |
grep project |
grep -v grep |
awk '{print $2}' |
tee /tmp/awk.log.$$ |
xargs kill -15
Review the logs and see that your script is one of the processes being killed.
The crontab entry contains:
/home/myname/project/stopWithZip.sh >> /home/myname/project/cronlog/$(date +"\%F")-stop.log 2>&1
When ps lists that, it contains 'project' and does not contain 'grep' so the kill in the script kills the script itself.
When you run it from the command line (using a conventional '$' as the prompt), you run:
$ ./stopWithZip.sh
and when ps lists that, it does not contain 'project' so it is not killed.
If you ran:
$ /home/myname/project/stopWithZip.sh >> /home/myname/project/cronlog/$(date +"\%F")-stop.log 2>&1
from the command line, like you do with cron (crontab), you would find it fails.

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