Validate password less authentication with n number of hosts.

I need to check plenty of servers everyday. because of few servers down or changes happend… password less authentication is failing on few hosts. I need a command or script to verify that password less authentication is working fine or not on all the servers.

Usually… I get the server name on all the servers using **ssh -q <servername> uname -a **
If servers are down or key is not working… my script is getting stuck in the middle. I want to avoid it.


Submit an answer
You can type!ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.


If you’re using a bash script to check the status, you could use something relatively simple, such as:

    local username="${1}"
    local hostname="${2}"
    local privatekey="${3}"
    local checkConn=$(ssh ${username}@${hostname} -i ${privatekey} "echo 2>&1" && echo UP || DOWN)

    if [ "${checkConn}" == "DOWN" ];
        # Action taken when host is down.
        echo DOWN
        # Action taken when host is up.
        echo UP

checkSsh "${1}" "${2}" "${3}"

You’d then pass on the details:

./ root 111.222.333.444 /path/to/key

You could even reduce that down to:

if ssh ${1}@${2} -i ${3} "echo 2>&1"; then
    echo UP
    echo DOWN

And replace the echo UP|DOWN with whatever action you needed to perform. Or, if the user you’re trying to login as to test is always the same:

if ssh root@${1} -i ${2} "echo 2>&1"; then
    echo UP
    echo DOWN