welcome: please sign in

Diff for "SetupNewMachines"

Differences between revisions 21 and 51 (spanning 30 versions)
⇤ ← Revision 21 as of 2008-03-02 20:20:57 →
Size: 6232
Editor: dhcp-37-70
Comment:
← Revision 51 as of 2008-03-02 23:19:26 → ⇥
Size: 8521
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. These steps are listed in approximately the order in which they should be performed; please try to maintain that.
Line 3: Line 3:
These steps are listed in approximately the order in which they should be performed; please try to maintain that. === List the Machine on the Wiki ===

Add the machine to the ["Hardware"] page.

It is a very good idea to photograph the front and back panels of the machine and put those images on the wiki page; that way remote admins and people in the data center can be sure they're talking about the same ports.
Line 13: Line 17:
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 23: Line 27:
We use Debian. Install it. We use Debian. Install it. We should put our standard {{{/etc/apt/sources.list}}} here.
Line 31: Line 35:
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 38:
  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 59:
}}}

Also be sure to

{{{
  apt-get install module-assistant build-essential module-init-tools
Line 75: Line 81:
Do this and check that /afs shows up. Do this and check that {{{/afs}}} shows up.
Line 83: Line 89:
  dpkg -i /afs/hcoop.net/common/debian/libnss-afspag/*.deb
Line 90: Line 97:
=== Optional Steps ===

==== {{{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.
Line 105: Line 99:
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. '''''VERY IMPORTANT''''': put exactly the following in {{{/etc/krb5.conf}}} -- no more, no less

{{{
[libdefaults]
 default_realm = HCOOP.NET
 kdc_timesync = 1
 forwardable = true
 proxiable = true
[logging]
        default = FILE:/proc/self/fd/2
}}}
Line 109: Line 114:
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 111: Line 116:
 1. the userid for a given username
 2. the username for a userid		  1. the userid for a given username and vice versa
 2. the groupid for a given groupname and vice versa
Line 117: Line 122:
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. The {{{libnss-afspag}}} package makes PAGs show up as a special group. To enable these changes, edit {{{/etc/nsswitch.conf}}} and change the {{{passwd}}} and {{{group}}} lines to look like this:
Line 120: Line 125:
passwd:        ptdb files
group:        afspag files
shadow: files 		passwd: ptdb files
group: afspag files
Line 127: Line 131:
PAM is the mechanism used by Linux to do the following: PAM is Linux's mechanism to do the following:
Line 135: Line 139:
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 145: Line 149:
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 148: Line 152:
   kadmin -r HCOOP.NET
     ank -randkey host/server.hcoop.net@HCOOP.NET
     ktadd -k /etc/krb5.keytab
     quit		    rm -f /etc/krb5.keytab # important -- if it already exists the new key will merely be appended
   kadmin -r HCOOP.NET -q 'ank -randkey host/server.hcoop.net@HCOOP.NET'
   kadmin -r HCOOP.NET -q 'ktadd -k /etc/krb5.keytab host/server.hcoop.net@HCOOP.NET'
Line 156: Line 159:
Then these lines to /etc/ssh/sshd_config: Then these lines to {{{/etc/ssh/sshd_config}}}:
Line 164: Line 167:

=== 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. List the Machine on the Wiki

Add the machine to the ["Hardware"] page.

It is a very good idea to photograph the front and back panels of the machine and put those images on the wiki page; that way remote admins and people in the data center can be sure they're talking about the same ports.

2. 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.

3. Add a DNS entry for the server

Straightforward.

4. Install Debian

We use Debian. Install it. We should put our standard /etc/apt/sources.list here.

5. 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.

6. 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.

7. 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/libnss-afspag/*.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").

8. Configure Kerberos

VERY IMPORTANT: put exactly the following in /etc/krb5.conf -- no more, no less 

[libdefaults]
        default_realm = HCOOP.NET
        kdc_timesync = 1
        forwardable = true
        proxiable = true
[logging]
        default = FILE:/proc/self/fd/2

9. Configure Name Service

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

  1. the userid for a given username and vice versa
  2. the groupid for a given groupname and vice versa
  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. The libnss-afspag package makes PAGs show up as a special group. To enable these changes, edit /etc/nsswitch.conf and change the passwd and group lines to look like this: 

passwd:  ptdb   files
group:   afspag files

10. 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.

11. 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   # important -- if it already exists the new key will merely be appended
   kadmin -r HCOOP.NET -q 'ank -randkey host/server.hcoop.net@HCOOP.NET'
   kadmin -r HCOOP.NET -q 'ktadd -k /etc/krb5.keytab host/server.hcoop.net@HCOOP.NET'
   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

12. Optional Steps

12.1. Performance-Tune the OpenAFS Client

FIXME: AdamM needs to fill this in

12.2. 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".

12.3. 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)