{{tag>Redhat Cluster}}

= Script de test STONITH fencing cluster

Voir :
* [[https://en.wikipedia.org/wiki/STONITH|STONITH]]
* [[https://en.wikipedia.org/wiki/Fencing_(computing)|Fencing]]
* [[https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/High_Availability_Add-On_Reference/ch-fencing-HAAR.html|Fencing Redhat]]

Voir aussi :
* [[http://meinit.nl/virtualbox-fencing-and-red-hat-enterprise-linux-cluster-suite|Script pour VirtualBox]]
* [[https://fedorahosted.org/cluster/wiki/FenceArch|Script en Python]]

Source :
* https://github.com/wklxd/misc/blob/master/fence_ssh


Ce script permet d'émuler le "fencing" via SSH, à des fins de test.
Compatible cman, pacemaker et pcs

''/usr/sbin/fence_ssh''
<code bash>
#!/bin/sh

# A fence agent for cman and pacemaker, using ssh.
# The only required argument is nodename.
# Author:
#        klwang (http://klwang.info)
# Note:
#        authorized_keys configuration are required
#        just for test, enjoy it!
# Source : https://github.com/wklxd/misc/blob/master/fence_ssh


SSH_COMMAND="/usr/bin/ssh -q -x -o PasswordAuthentication=no -o StrictHostKeyChecking=no -n -l root"
#REBOOT_COMMAND="echo '/sbin/reboot -nf' | SHELL=/bin/sh at now >/dev/null 2>&1"
REBOOT_COMMAND="shutdown -r now >/dev/null 2>&1"
nodename=
action=reboot

usage () {
    /bin/echo "Usage: $0 -n NAME [-o ACTION]"
    /bin/echo
    /bin/echo " -n NODENAME"
    /bin/echo "   The name of the node to be fenced."
    /bin/echo "   In case it contains spaces, use double quotes."
    /bin/echo " -o ACTION"
    /bin/echo "   What to do; on|off|list|monitor|reboot(default)."
    /bin/echo
    exit 0
}

arg_cmd() {
    while getopts ":n:p:o:h" opt; do
        case "$opt" in
        n|p)
            nodename=$OPTARG
            ;;
        o)
            action=$OPTARG
            ;;
        h)
            action="usage"
            ;;
        *)
            usage
            ;;
        esac
    done
}

arg_stdin() {
    eval $(cat -)
    if [ "x$nodename" = "x" -a "x$port" != "x" ]; then
        nodename=$port         # pacemaker only use port
    fi
}

metadata() {

cat <<EOF
<?xml version="1.0" ?>
<resource-agent name="fence_ssh" shortdesc="ssh fence agent, work both for cman and pacemaker">
<longdesc>
The style come from fence_pcmk, http://www.clusterlabs.org
Some functions references external/ssh agent
</longdesc>
<vendor-url> http://klwang.info </vendor-url>
<parameters>
        <parameter name="action" unique="1">
                <getopt mixed="-o" />
                <content type="string" default="reboot" />
                <shortdesc lang="en">Fencing Action</shortdesc>
        </parameter>
        <parameter name="nodename" unique="1">
                <getopt mixed="-n" />
                <content type="string"  />
                <shortdesc lang="en">Name of machine</shortdesc>
        </parameter>
        <parameter name="port" unique="1">
                <getopt mixed="-p" />
                <content type="string"  />
                <shortdesc lang="en">Name of machine, equal to nodename</shortdesc>
        </parameter>
        <parameter name="help" unique="1">
                <getopt mixed="-h" />
                <content type="string"  />
                <shortdesc lang="en">Display help and exit</shortdesc>
        </parameter>
</parameters>
<actions>
        <action name="reboot" />
        <action name="on" />
        <action name="off" />
        <action name="list" />
        <action name="status" />
        <action name="metadata" />
</actions>
</resource-agent>
EOF

    exit 0
}

get_usable_ip() {

    for ip in `/usr/bin/getent hosts $1 | cut -d" " -f1`; do
        if ping -w1 -c1 $ip > /dev/null 2>&1
        then
            echo $ip
            return 0
        fi
    done
    return 1

}

is_host_up() {

    for j in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15; do
        if
            ping -w1 -c1 "$1" >/dev/null 2>&1
        then
            sleep 1
        else
            return 1
        fi
    done
    return 0

}

reboot() {

    local node=$1
    ip=`get_usable_ip $node`
    if [ $? -ne 0 ];then
        /bin/echo "Error: can not get a usable ip, is nodename($node) alive!"
        exit 0                       # in case power lose
    fi

    if ! ping -c1 -w1 $ip >/dev/null 2>&1; then
        exit 0                       # in case the node have been fenced
    fi

    $SSH_COMMAND $ip "echo $(date +'%Y-%m-%d %H:%M') FENC_FROM_SSH \$SSH_CLIENT >> /var/log/fenc.log"
    $SSH_COMMAND $ip "$REBOOT_COMMAND"

    if `is_host_up $ip`; then
        exit 1
    else
        exit 0
    fi

}

#main

if [ $# -gt 0 ]; then
    arg_cmd $*
else
    arg_stdin
fi


case "$action" in

    metadata)
        metadata
        ;;
    usage)
        usage
        ;;
    on|off)
        exit 0        # ssh can not turn on a node
                      # so avoiding turn it down
        ;;
    reset|reboot)
        reboot $nodename
        ;;
    monitor)
        exit 0        # just for pacemaker
        ;;
    help)
        usage
        ;;
    *)
        /bin/echo "Unkonw options"
        exit 1
        ;;
esac
</code>

Configuration
<code bash>
pcs stonith create fencessh_node1 fence_ssh nodename=node1 pcmk_host_list=node1
pcs stonith create fencessh_node2 fence_ssh nodename=node2 pcmk_host_list=node2
pcs stonith level add 1 node1 fencessh_node1
pcs stonith level add 1 node2 fencessh_node2

# Interdire le fence de soi-même
pcs constraint location fencessh_node1 avoids node1
pcs constraint location fencessh_node2 avoids node2
</code>

Test
<code bash>
pcs stonith fence node2
</code>


== Autres 

Lister
<code bash>
pcs stonith list
stonith_admin -I
</code>