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Objective: I want to write a Python test script to execute a reboot command through SSH on a remote Linux machine, capture the boot logs and check if the boot is successful.

Problem: I am able to send a reboot command using Paramiko and the machine reboots as expected, but I couldn't capture the boot logs and print them out. My code also seems to run without waiting for the boot process to finish.

Here is part of my code:

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
try:
    ssh.connect(host, username=username, password=password)
except paramiko.SSHException as e:
    ssh.get_transport().auth_none(username)  # without password

# execute reboot and capture the boot logs
stdin, stdout, stderr = ssh.exec_command("/sbin/reboot")
print(stdout.readlines())
print(stderr.readlines())

# check if reboot is done
exit_status = ''
msg = ''
while True:
    if stdout_channel.exit_status_ready():
        exit_status = ssh.stdout.channel.recv_exit_status()
        print("Exit status: %s" % exit_status)
        break
    time.sleep(10)

ssh.close()
if exit_status == 0:
    print("Reboot successful")
else:
    print(Reboot not successful")

Logs are not captured and the following output is printed out before the machine finishing rebooting:

[]
[]
Exit status: 0
Reboot successful

Questions:

a) How can I capture the boot logs?

b) How to properly check for status after boot process is completed? Alternatively, I think I can ssh again and simply run a command after waiting some time for it to reboot.

Michael Tan
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1 Answers1

0

  1. you need /var/log/boot.log or /var/log/dmesg

  2. You need monitoring. Generally, for LAN you need something like zabbix, but it is to much for 2 hosts. Other way is any script for sending message from remote host to your log server or messenger(using messenger API) or vice versa. For your script you can make systemd Unit service for run it after/before anything.

Vldmr
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