wiki:telehouse_serial_access

Version 24 (modified by Jamie McClelland, 12 years ago) (diff)

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How do I connect to an MF/PL server located at Telehouse via the serial port?

In the MF/PL Telehouse rack, we have installed two Octopus 550's in sylvia, a domU that is installed on octavia. An Octopus 550 is a pci card that has 8 serial lines coming out of it. octavia already has two built-in serial lines. octavia's first built-in serial line is outputting the console for octavia itself. The second built-in serial line is reserved (it will probably be used to control a power system). The remaining 16 serial lines are connected to other servers in our rack.

  • Out:
    • octavia's bootloader, hypervisor console, kernel console, and getty run on built-in serial port 1, (octavia: ttyS0)
  • In:
    • reserved (built-in serial port 2)
    • Octopus (Top, IRQ 19)
      • viewsic (Cable 1, sylvia: ttyS0)
      • malcolm (Cable 2, sylvia: ttyS1)
      • chavez (Cable 3, sylvia: ttyS2)
      • gramsci (Cable 4, sylvia: ttyS3)
      • sontag (Cable 5, sylvia: ttyS4)
      • menchu (Cable 6, sylvia: ttyS5)
      • leslie (Cable 7, sylvia: ttyS6)
      • evo (Cable 8, sylvia: ttyS7)
    • Ocotpus (Bottom, IRQ 20)
      • shadow (Cable 1, sylvia: ttyS8)
      • goofball (Cable 2 sylvia: ttyS9)
      • tenant (Cable 3 sylvia: ttyS10)
      • robeson (Cable 4 sylvia: ttyS11)
      • algernon (Cable 5 sylvia: ttyS12)
      • sprocket (Cable 6 sylvia: ttyS13)
      • zinn (Cable 7 sylvia: ttyS14)
      • fred (Cable 8 sylvia: ttyS15)

The serial consoles of the attached machines are all remotely accessible (to properly-authenticated people), and they are also logged and timestamped. We are using cereal to do this cleanly and easily.

In order to connect via serial console to one of the servers named above, ssh into console.mayfirst.org as servername-console

For example:

ssh -t leslie-console@console.mayfirst.org cereal attach leslie

Would give you full read/write access to the console on leslie.

The SSH RSA host key for console.mayfirst.org should have a fingerprint of:

2048 04:18:0f:cc:c9:2e:79:78:2e:91:f0:f2:f4:67:90:f8 console.mayfirst.org,209.51.172.10

We can also setup additional users that have read-only access to the sessions created by each of these usernames, should that be desirable. You can request such access by creating a ticket.

In addition - we have a serial line running from leslie's /dev/ttyUSB0 that goes to octavia's built-in serial port 1, so that octavia's console itself is remotely accessible, and logged. You can connect to octavia's console with:

ssh -t octavia-console@leslie.mayfirst.org cereal attach octavia

Setting up a new console user

To setup a new console user, type the following on sylvia:

adduser --disabled-password --gecos='fred console user,,,' fred-console
cereal-admin create fred /dev/ttyS15 115200 fred-console fred-console
cereal-admin start fred