| # Copyright (c) 2011 The Chromium OS Authors. All rights reserved. |
| # Use of this source code is governed by a BSD-style license that can be |
| # found in the LICENSE file. |
| |
| def make_ssh_command(user='root', port=22, opts='', hosts_file=None, |
| connect_timeout=None, alive_interval=None): |
| """Override default make_ssh_command to use options tuned for Chrome OS. |
| |
| Tuning changes: |
| - ConnectTimeout=30; maximum of 30 seconds allowed for an SSH connection |
| failure. Consistency with remote_access.sh. |
| |
| - ServerAliveInterval=180; which causes SSH to ping connection every |
| 180 seconds. In conjunction with ServerAliveCountMax ensures that if the |
| connection dies, Autotest will bail out quickly. Originally tried 60 secs, |
| but saw frequent job ABORTS where the test completed successfully. |
| |
| - ServerAliveCountMax=3; consistency with remote_access.sh. |
| |
| - ConnectAttempts=4; reduce flakiness in connection errors; consistency |
| with remote_access.sh. |
| |
| - UserKnownHostsFile=/dev/null; we don't care about the keys. Host keys |
| change with every new installation, don't waste memory/space saving them. |
| |
| - SSH protocol forced to 2; needed for ServerAliveInterval. |
| """ |
| base_command = ('/usr/bin/ssh -a -x %s -o StrictHostKeyChecking=no' |
| ' -o UserKnownHostsFile=/dev/null -o BatchMode=yes' |
| ' -o ConnectTimeout=30 -o ServerAliveInterval=180' |
| ' -o ServerAliveCountMax=3 -o ConnectionAttempts=4' |
| ' -o Protocol=2 -l %s -p %d') |
| return base_command % (opts, user, port) |
