reboot() snippet for 2.x

[hyperknot]

The official docs states:

No equivalent has been written for modern Fabric; now that the connection/client objects are made explicit, one can simply instantiate a new object with the same parameters (potentially with sufficient timeout parameters to get past the reboot, if one doesn’t want to manually call something like time.sleep.)

I'm totally happy with that approach, however could you give a snippet for replicating the 1.x's reboot-and-wait-reconnect functionality? I guess it has to be some kind of time.sleep(1) loop, but I'm not clear about the connection management part.

[theno]

I use this in my fabric-2.x scripts:

import sys
import time

import paramiko.ssh_exception


# related links for reboot with fabric-2.x
# * fabric-1.x:
#   https://github.com/fabric/fabric/blob/c0224a52df59821f21a8c0bd47ce15e42c2046a4/fabric/operations.py#L1244
# * snippet: https://github.com/fabric/fabric/issues/1904
# * timings: https://github.com/fabric/fabric/issues/1488
def reboot(c):
    '''Reboot remote host and wait until the remote host is up again.

    Also print out how long the reboot has taken.

    NoValidConnectionsError after timeout or any unexpected Exception will be raised.
    '''
    start_time = time.time()
    c.run('reboot', warn=True)

    time.sleep(5)

    # wait until the reboot has been finished
    timeout = time.time() + 120
    while True:
        try:
            c.run(
                'whoami',  # use `whoami` as a no-op
                echo=False, hide=True,
            )
            break
        except paramiko.ssh_exception.NoValidConnectionsError as exc:
            sys.stdout.write('.')
            sys.stdout.flush()
            if time.time() > timeout:
                raise exc
            time.sleep(1)

    print('reboot took {:.0f} seconds'.format(time.time() - start_time))

[vsilent]

We use following approach

 with fabric.api.settings(host_string=server_ip, user="root"):       
        connect_attempts = 10
        for _ in range(connect_attempts):
            try:    
               fabric.api.execute('uname -a')
               break
            except BaseException as e:     #  use paramiko exceptions here   
               time.sleep(10)

[alias454]

This helped me solve my problem. I went with this approach

def cmd_wait(con, run_cmd):
    # May take up to 5 minutes
    sleep(5)
    ret = 'Command took too long to finish'
    for _ in range(25):
        try:
            ret = con.run(run_cmd, hide=True)
            break
        except (ConnectionError, NoValidConnectionsError):
            sleep(10)

    return ret

Then I call it like so

session = connect(hostname, username, password)

is_rebooted = session.sudo('nohup sudo -b bash -c "sleep 5 && reboot"', hide=True)
if is_rebooted.return_code == 0:
    is_running = cmd_wait(session, 'uptime')
    if is_running.return_code == 0:
        print('[OK] Reboot successful: ' + hostname)
    else:
        print('[FAIL] Status Check: ' + hostname)