Date created: Tuesday, June 20, 2017 12:11:22 PM. Last modified: Wednesday, December 11, 2024 12:00:49 PM
Running Parallel Commands via SSH
References
https://dataplumber.wordpress.com/2016/10/26/issuing-junos-commands-using-ansible-raw-module/
Examples
Running a single command on multiple remote devices using Ansible:
ansible all -i hosts -m raw -c paramiko -a "wr mem"
Using parallel SSH (pssh):
pssh -h hosts.txt -l username --askpass -o /output_dir/ "wr mem"
Ciscocmd expect script:
./ciscocmd -u username -p password -T hosts.txt -r commands.txt -l log-file-prefix- -Y
When using SSH on Linux the -T option tells SSH not to allocate a PTY so that when run from a cron job the tasks can accept stdin/out from the session (e.g. log to a file). The -q option will suppress any devices banners. Specifying /dev/zero as an input will hold the SSH command running incase there is a delay in stdout opening. Having "-oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null" is potentially insecure and may not be suitable for a production network.
RAW_OUTPUT=$(timeout $TIMEOUT sshpass -e ssh -T -q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null $USER@$HOST "$CMD" </dev/zero 2>/dev/null)
BASH space seperated values:
ips="10.254.255.16 10.254.255.2 10.254.254.50 10.254.248.2" for ip in $ips; do echo "$ip:"; ssh -q -T $username@$ip "show vpdn group"; echo ""; done # Alternatively ips="10.254.255.16 10.254.255.2 10.254.254.50 10.254.248.2" export SSHPASS="mypass" for ip in $ips; do echo "$ip:"; sshpass -e ssh -q -T $username@$ip "show vpdn group"; echo ""; done
BASH script using a for loop over a hosts file:
#!/bin/bash set -u USER="myuser" export SSHPASS="mypass" TIMEOUT=10s CMD="show ver | i uptime" while read -r HOST || [[ -n "$HOST" ]] do timeout $TIMEOUT sshpass -e ssh -n -q -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null -oBatchMode=no $USER@$HOST "$CMD" 2>/dev/null & # Not all SSH versions support the -q and -o options used here ^ done < hosts.txt
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