Check if a ZFS storage pool is active

    zpool : string
        Name of storage pool

    CLI Example:

    .. code-block:: bash

        salt '*' zpool.exists myzpool

def exists(zpool):
    '''
    Check if a ZFS storage pool is active

    zpool : string
        Name of storage pool

    CLI Example:

    .. code-block:: bash

        salt '*' zpool.exists myzpool

    '''
    # list for zpool
    # NOTE: retcode > 0 if zpool does not exists
    res = __salt__['cmd.run_all'](
        __utils__['zfs.zpool_command'](
            command='list',
            target=zpool,
        ),
        python_shell=False,
        ignore_retcode=True,
    )

    return res['retcode'] == 0