welcome: please sign in

Diff for "SetupNewMachines"

Differences between revisions 19 and 37 (spanning 18 versions)
⇤ ← Revision 19 as of 2008-03-02 20:20:04 →
Size: 6190
Editor: dhcp-37-70
Comment:
← Revision 37 as of 2008-03-02 20:55:44 → ⇥
Size: 7945
Editor: dhcp-37-70
Comment:
Deletions are marked like this. Additions are marked like this.
Line 1: Line 1:
This is just a rough sketch for now; we will expand it soon.
Line 13: Line 11:
Functions 1+2 are typically provided by kvm.hcoop.net; assuming you plan on going with that, you should connect the server's keyboard and video to the kvm switch. Functions 1+2 are typically provided by {{{kvm.hcoop.net}}} (see KvmAccess); assuming you plan on going with that, you should connect the server's keyboard and video to the kvm switch.
Line 31: Line 29:
You should install the {{{openafs-client}}}, {{{openafs-krb5}}}, {{{openafs-modules-source}}}, {{{openafs-dbg}}}, {{{openafs-doc}}}, {{{libopenafs-dev}}}, packages from {{{/afs/hcoop.net/common/debian/}}}. Here is a block of commands to cut and paste if you are lazy: First, give our preferences to {{{debconf}}}:
Line 34: Line 32:
  apt-get install krb5-user libkrb5-dev   debconf openafs-client/thiscell HCOOP.NET
  debconf openafs-client/dynroot true
  debconf openafs-client/cachesize 500000 # cache size in kB; default is way too small
}}}

You should install the {{{module-assistant}}}, {{{build-essential}}}, {{{module-init-tools}}}, {{{openafs-client}}}, {{{openafs-krb5}}}, {{{openafs-modules-source}}}, {{{openafs-dbg}}}, {{{openafs-doc}}}, {{{libopenafs-dev}}}, packages from {{{/afs/hcoop.net/common/debian/}}}. Here is a block of commands to cut and paste if you are lazy:

{{{
  apt-get install krb5-user libkrb5-dev module-assistant build-essential module-init-tools
Line 47: Line 53:
}}}

Also be sure to

{{{
  apt-get install module-assistant build-essential module-init-tools
Line 75: Line 75:
Do this and check that /afs shows up. Do this and check that {{{/afs}}} shows up.
Line 88: Line 88:
The first three packages are explained below; the last one is the {{fsr}} command (recursive "{{{fs}}}").

=== runit ===

The runit package is useful for launching and monitoring daemons with '''clean process state'''. This is often important when dealing with tokens and pags.

=== dnscache ===

You can install the dnscache package to make the server self-sufficient for dns resolution purposes (it acts as a tiny dns server just for localhost). This improves the reliability of the overall infrastructure.

There is a copy of this package in /afs/megacz.com/debian/; the author of the software recently changed its license, so it will be a standard package in the next release of debian (it may even be in etch-backports already).

Starting dnscache via runit is often a good idea; this ensures that it starts early in the boot process and that it is restarted if it dies for any reason.		 The first three packages are explained below; the last one is the {{{fsr}}} command (recursive "{{{fs}}}").
Line 104: Line 92:
You should copy /etc/krb5.conf from deleuze to the new server. This is VERY IMPORTANT. What is NOT in this file is also almost as important as what IS in this file, so think three times before adding or removing anything. You should copy {{{/etc/krb5.conf}}} from deleuze to the new server. This is VERY IMPORTANT. What is NOT in this file is also almost as important as what IS in this file, so think three times before adding or removing anything.
Line 108: Line 96:
The {{{libnss-ptdb}}} package lets linux use the AFS {{{ptserver}}} (protection server) as a name service. The {{{ptserver}}} keeps track of all the users in AFS. A "name service" is Linux's mechanism for answering these four queries: A "name service" is Linux's mechanism for answering these queries:
Line 116: Line 104:
To make {{{ptserver}}} our primary choice for name service, edit {{{/etc/nsswitch.conf}}} and change the following three lines to look like this: The {{{libnss-ptdb}}} package lets linux use the AFS user database (the {{{ptserver}}} or protection server) as a name service. To make {{{ptserver}}} our primary choice for name service, edit {{{/etc/nsswitch.conf}}} and change the following three lines to look like this:
Line 126: Line 114:
PAM is the mechanism used by Linux to do the following: PAM is Linux's mechanism to do the following:
Line 134: Line 122:
Mostly this consists of copying mire's /etc/pam.d/*, although it would be a good idea to state precisely which parts of that need to be copied. Mostly this consists of copying mire's {{{/etc/pam.d/*}}}, although it would be a good idea to state precisely which parts of that need to be copied.  Also should document the mechanism used on deleuze and other non-member servers to restrict logins to admins only.
Line 144: Line 132:
Add this principal to the KDC like this (execute these commands on the new server, as root, while holding admin tokens): Add this principal to the KDC like this (execute these commands on the new server, as root, while holding admin tickets):
Line 147: Line 135:
   rm -f /etc/krb5.keytab # just in case
Line 149: Line 138:
     ktadd -k /etc/krb5.keytab      ktadd -k /etc/krb5.keytab host/server.hcoop.net@HCOOP.NET
Line 155: Line 144:
Then these lines to /etc/ssh/sshd_config: Then these lines to {{{/etc/ssh/sshd_config}}}:
Line 163: Line 152:

=== Optional Steps ===

==== Performance-Tune the OpenAFS Client ====

FIXME: AdamM needs to fill this in

==== runit ====
The runit package is a mechanism for starting, stopping, and monitoring daemons. It is an alternative to the traditional {{{/etc/init.d}}} and {{{start-stop-daemon}}} scheme. Its chief advantages are:

  1. It launches daemons with '''clean process state'''; the daemon inherits nothing from the administrator invoking the start/stop command because the daemon is not forked as a child of the administrator's shell (rather, a request is sent {{{runit}}} daemon asking it to fork the daemon). This is very important when dealing with tokens and pags.
  2. Runit monitors the processes that it forks, and restarts them if they die.
  3. Runit eliminates the need for pidfiles and the associated risk of starting multiple copies of a daemon.
  4. Runit captures the daemon's {{{stdout}}} and either sends it to a logger (if specified) or else displays it in the process name (output of {{ps}})

{{{
   apt-get install runit
}}}
When you move a process from {{{/etc/init.d/}}} control to {{{runit}}} supervision, you should inform debian that you have done so:
{{{
  # assuming /var/service/$SERVICE/run is the runit script
  dpkg-divert --rename /etc/init.d/$SERVICE
  ln -s /usr/bin/sv /etc/init.d/$SERVICE
}}}
This will cause invocations of {{{/etc/init.d/script {start|stop} }}} to do "the right thing".

==== dnscache ====

You can install the dnscache package to make the server self-sufficient for dns resolution purposes (it acts as a tiny dns server just for localhost). This improves the reliability of the overall infrastructure. There is a copy of this package in {{{/afs/megacz.com/debian/dnscache/}}}; the author of the software recently changed its license, so it will be a standard package in the next release of debian (it may even be in etch-backports already; when it is, this paragraph should be updated to recommend that instead).

Starting dnscache via runit is often a good idea; this ensures that it starts early in the boot process and that it is restarted if it dies for any reason.

These steps are listed in approximately the order in which they should be performed; please try to maintain that.

1. Set Up Out Of Band Access

All machines owned by hcoop should, if possible, have some out-of-band mechanism for:

  1. Keyboard access
  2. Screen access
  3. Power-cycling

Functions 1+2 are typically provided by kvm.hcoop.net (see KvmAccess); assuming you plan on going with that, you should connect the server's keyboard and video to the kvm switch.

Each server has its own solution for 3, usually in the form of a "service processor". You should investigate and document the appropriate service processor settings. If the service processor requires its own IP address, you should name it foo-sp.hcoop.net where foo.hcoop.net is the name of the server.

2. Add a DNS entry for the server

Straightforward.

3. Install Debian

We use Debian. Install it.

4. Compile a Kernel

It is generally a good idea for hcoop to compile its own kernels. Regarding statically-compiled kernels, see StaticallyCompiledKernels for some opinions.

5. Install the AFS Client

First, give our preferences to debconf: 

  debconf openafs-client/thiscell  HCOOP.NET
  debconf openafs-client/dynroot   true
  debconf openafs-client/cachesize 500000      # cache size in kB; default is way too small

You should install the module-assistant, build-essential, module-init-tools, openafs-client, openafs-krb5, openafs-modules-source, openafs-dbg, openafs-doc, libopenafs-dev, packages from /afs/hcoop.net/common/debian/. Here is a block of commands to cut and paste if you are lazy: 

  apt-get install krb5-user libkrb5-dev module-assistant build-essential module-init-tools
  mkdir -p /tmp/openafs-packages
  cd /tmp/openafs-packages
  scp ssh.hcoop.net:/afs/hcoop.net/common/debian/openafs/1.4.6/\*.deb      ./
  dpkg -i \
    openafs-client*.deb         \
    openafs-krb5*.deb           \
    openafs-modules-source*.deb \
    openafs-dbg*.deb            \
    openafs-doc*.deb            \
    libopenafs-dev*.deb         
  cd /tmp
  rm -rf /tmp/openafs-packages

Once these packages are installed, you will want to run 

  module-assistant a-i -t openafs-modules

... assuming you compiled your own kernel and the compiled kernel tree resides in /usr/src/linux. If this is not the case, you are on your own.

If the command above completes, it will have created and installed a .deb containing the kernel module. You may need to run 

  /etc/init.d/module-init-tools start

to refresh whatever module wonkery linux maintains in obscure locations. Once this is figured out (if all else fails, reboot) you should be able to 

  /etc/init.d/openafs-client start

Do this and check that /afs shows up.

6. Install Packages

Now that afs is up, you can easily install packages. The block of commands below installs the set of packages which must be on every hcoop server (this list will be expanded as necessary). 

  dpkg -i /afs/hcoop.net/common/debian/libnss-ptdb/*.deb
  dpkg -i /afs/hcoop.net/common/debian/libpam-afs-session/*.deb
  dpkg -i /afs/hcoop.net/common/debian/libpam-krb5/*.deb
  dpkg -i /afs/hcoop.net/common/debian/fsr/*.deb

The first three packages are explained below; the last one is the fsr command (recursive "fs").

7. Configure Kerberos

You should copy /etc/krb5.conf from deleuze to the new server. This is VERY IMPORTANT. What is NOT in this file is also almost as important as what IS in this file, so think three times before adding or removing anything.

8. Configure Name Service

A "name service" is Linux's mechanism for answering these queries:

  1. the userid for a given username
  2. the username for a userid
  3. the home directory for a user
  4. the shell for a user
  5. what groups a user is in

The libnss-ptdb package lets linux use the AFS user database (the ptserver or protection server) as a name service. To make ptserver our primary choice for name service, edit /etc/nsswitch.conf and change the following three lines to look like this: 

passwd:         ptdb   files
group:          afspag files
shadow:                files

9. Configure PAM

PAM is Linux's mechanism to do the following:

  1. decide if somebody is who they say they are (authentication; in our case via kerberos)

  2. set up sessions (in the case of AFS, this means creating PAGs)

  3. change passwords (in our case, changing the password in the KDC)

FIXME

Mostly this consists of copying mire's /etc/pam.d/*, although it would be a good idea to state precisely which parts of that need to be copied. Also should document the mechanism used on deleuze and other non-member servers to restrict logins to admins only.

10. Configure SSH

You will need to create a "host principal" for the new server; if you are setting up server.hcoop.net, then it must have the name 

   host/server.hcoop.net@HCOOP.NET

Add this principal to the KDC like this (execute these commands on the new server, as root, while holding admin tickets): 

   rm -f /etc/krb5.keytab   # just in case
   kadmin -r HCOOP.NET
     ank -randkey host/server.hcoop.net@HCOOP.NET
     ktadd -k /etc/krb5.keytab host/server.hcoop.net@HCOOP.NET
     quit
   chown root:root /etc/krb5.keytab
   chmod go-rwx /etc/krb5.keytab

Then these lines to /etc/ssh/sshd_config: 

  GssapiKeyExchange yes
  GssapiAuthentication yes
  GSSAPICleanupCredentials no
  UsePAM yes

11. Optional Steps

11.1. Performance-Tune the OpenAFS Client

FIXME: AdamM needs to fill this in

11.2. runit

The runit package is a mechanism for starting, stopping, and monitoring daemons. It is an alternative to the traditional /etc/init.d and start-stop-daemon scheme. Its chief advantages are:

  1. It launches daemons with clean process state; the daemon inherits nothing from the administrator invoking the start/stop command because the daemon is not forked as a child of the administrator's shell (rather, a request is sent runit daemon asking it to fork the daemon). This is very important when dealing with tokens and pags.

  2. Runit monitors the processes that it forks, and restarts them if they die.
  3. Runit eliminates the need for pidfiles and the associated risk of starting multiple copies of a daemon.

  4. Runit captures the daemon's stdout and either sends it to a logger (if specified) or else displays it in the process name (output of ps) 

   apt-get install runit

When you move a process from /etc/init.d/ control to runit supervision, you should inform debian that you have done so: 

  # assuming /var/service/$SERVICE/run is the runit script
  dpkg-divert --rename /etc/init.d/$SERVICE
  ln -s /usr/bin/sv /etc/init.d/$SERVICE

This will cause invocations of /etc/init.d/script {start|stop}  to do "the right thing".

11.3. dnscache

You can install the dnscache package to make the server self-sufficient for dns resolution purposes (it acts as a tiny dns server just for localhost). This improves the reliability of the overall infrastructure. There is a copy of this package in /afs/megacz.com/debian/dnscache/; the author of the software recently changed its license, so it will be a standard package in the next release of debian (it may even be in etch-backports already; when it is, this paragraph should be updated to recommend that instead).

Starting dnscache via runit is often a good idea; this ensures that it starts early in the boot process and that it is restarted if it dies for any reason.

SetupNewMachines (last edited 2012-12-20 21:13:00 by ClintonEbadi)