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SPO600 Servers

1,366 bytes added, 18:13, 7 November 2019
Common SSH Problems
[[Category:SPO600]]
{{Admon/important|Backup Your Data|These computers are NEVER backed up. Please save all important files on other storage. '''These machines may fail, be removed , be upgraded, or be reinstalled at any time.'''}}
In [[SPO600]], remote access to servers is provided for learning and project work. It is recommended that you also set up [[SPO600 Host Setup|a personal Linux system]].
== Preparatory Steps ==
In order to gain access to these computers, you must send an [[SSH]] key to your [[User:Chris Tyler|professor]].Please follow these instructions exactly:
# Follow the steps outlined under [[SSH#Using_Public_Keys_with_SSH|Using Public Keys with SSH]] to create your key.
# Copy the public key (<code>id_rsa.pub</code> or <code>id_dsa.pub</code>) to a file named <code>''yourUserId''.pub</code> -- for example, if your chosen user ID is "jldoe", save the key in the file <code>jldoejdoe.pub</code> using a command such as: <code>cp ~/.ssh/id_rsa.pub ''jldoejdoe''.pub</code>
# Attach that file to an e-mail message and send it to [mailto:chris.tyler@senecacollege.ca chris.tyler@senecacollege.ca] with the subject line "SPO600 Key".
== Available Servers ==
 
{{Admon/important|Changes for Fall 2019|The server configuration for Fall 2019 has changed -- previous mentions of these systems by name may have referred to different hardware. Note that additional servers may be added as the semester proceeds.}}
 
=== AArch64: aarchie ===
The current [[ARMv8]] A main AArch64 system is available, known as ''aarchie''. You can access this system at the hostname aarchie.cdot.systems; if you're using a command-line ssh system, you can access aarchie with a command such as this:  ssh '' or username''@aarchie.cdot.systems  === AArch64: bbetty === An additional AArch64 system is known as 'archie'bbetty''. This is a system that is currently located inside the [[EHL]]. To connect to this system, you have to go through the EHL gateway on port 2200.
If you're using a command-line ssh system, you can issue a command such as this:
ssh -p 2200 ''username''@ehl.cdot.systems
 
=== x86_64: xerxes ===
Our The x86_64 server system is known as '''xerxes'''. If you're using a command-line ssh system, you can issue access xerxes with a command such as this:
ssh ''username''@xerxes.cdot.systems
== Simplified SSH Access ==
== Simplified SSH Access ==If you're using OpenSSH (the ssh client used on most Linux systems and other platforms), you can simplify ssh command lines by placing host connection details in the file <code>~/.ssh/config</code>:
If you're using OpenSSH (the ssh client used on most Linux <!-- Host "aarchie" hostname "ehl.cdot.systems" user "YourUserID" port 2200 Host "bbetty" hostname "ehl.cdot.systems" user "YourUserID" port 2202 Host "ccharlie" hostname "ehl.cdot.systems and other platforms), you can simplify complex ssh command lines by placing host connection details in the file <code>~/" user "YourUserID" port 2205 Host "xerxes" hostname "xerxes.cdot.ssh/config</codesystems" user "YourUserId" -->:
Host "aarchie"
hostname "aarchie.cdot.systems"
user "YourUserID"
Host "bbetty"
hostname "ehl.cdot.systems"
user "YourUserID"
Host "xerxes"
hostname "xerxes.cdot.systems"
user "YourUserIdYourUserID
Once you have added these lines (inserting your user ID where appropriate) and set the permission on that file (<code>chmod 0600 ~/.ssh/config</code>) you can use these commands to access the servers:
ssh aarchie
ssh bbetty
ssh xerxes
You can similarly configure simplified access in most other SSH client programs.
 
== SSH Access from Other Client Systems ==
Remember that these machines are multi-user systems. Use the <code>w</code> or <code>who</code> commands to see who else is using them; you can also try using the <code>write</code> command to communicate with another user if required.
 
== OS Versions ==
 
Note that the servers may have different operating system releases.
== Backup Your Accounts ==
With other SSH clients:
# Your key must be in OpenSSH format when you send it to your professor; this format is used by the default SSH client on Mac OS/X and Linux as well as PuTTY. If it is in SSH2 format, used by some other client programs, you can convert it with this command on a Linux system with OpenSSH (such as Matrix):
 
ssh-keygen -i -f ~/.ssh/''SSH2_PUBLIC_KEY_FILE''.pub > ~/.ssh/''OPENSSH_PUBLIC_KEY_FILE''.pub
Your professor will do this automatically as part of the key processing; however, you will need to manually perform this step for any keys that you append to your <code>~/.ssh/authorized_keys</code> file(s).
== Disconnect/Reconnect Ability ==
The [[Screen Tutorial|screen]] utility provides disconnect/reconnect capability, which is very useful for unstable network connections, long interactive operations, and changing your work location.

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