#pragma section-numbers off

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

[[TableOfContents]]


=== 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.

=== 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.

=== Add a DNS entry for the server ===

Straightforward.

=== Install Debian ===

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

=== 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.

=== Install the AFS Client ===

First, give our preferences to {{{debconf}}}:

{{{
  echo 'openafs-client openafs-client/thiscell string hcoop.net' | debconf-set-selections
  echo 'openafs-client openafs-client/thiscell seen true'        | debconf-set-selections
  echo 'openafs-client openafs-client/dynroot boolean true'      | debconf-set-selections
  echo 'openafs-client openafs-client/dynroot seen true'         | debconf-set-selections
  echo 'openafs-client openafs-client/cachesize string 500000'   | debconf-set-selections
  echo 'openafs-client openafs-client/cachesize seen true'       | debconf-set-selections
  echo 'openafs-client openafs-client/cell-info string '         | debconf-set-selections
  echo 'openafs-client openafs-client/cell-info seen true'       | debconf-set-selections
  echo 'openafs-client openafs-client/run-client boolean true'   | debconf-set-selections
  echo 'openafs-client openafs-client/run-client seen true'      | debconf-set-selections
}}}

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

{{{
  apt-get install krb5-user libkrb5-dev module-init-tools kstart \
          module-assistant build-essential  bison flex debhelper # required in order to build the module
  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-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.

=== 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/user/m/me/megacz/public/libnss-afs/libnss-afs*.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/megacz.com/debian/fsr*.deb
}}}

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

=== Install Network Time Protocol Daemon ===

Kerberos and AFS will not work correctly unless the clocks of the client and server are synchronized to within a certain tolerance.  Therefore, it is important for us to have a daemon running that keeps the clock set properly.

{{{
  apt-get install ntp
}}}

=== Install LDAP Support ===

Logins etc. will not work correctly unless libpam-ldap is installed and configured:

{{{
  apt-get install libpam-ldap
}}}

Debconf answers:

{{{
libpam-ldap     shared/ldapns/base-dn   string  dc=hcoop,dc=net
libpam-ldap     shared/ldapns/ldap-server       string  ldap://69.90.123.67/
libpam-ldap     libpam-ldap/pam_password        select  exop
libpam-ldap     libpam-ldap/rootbinddn  string  cn=admin,dc=hcoop,dc=net
libpam-ldap     libpam-ldap/dbrootlogin boolean true
libpam-ldap     libpam-ldap/override    boolean true
libpam-ldap     shared/ldapns/ldap_version      select  3
libpam-ldap     libpam-ldap/dblogin     boolean false
}}}

You will also need to know LDAP admin password; see /etc/pam_ldap.secret on one of existing servers
and re-type the password into the password prompt.

=== 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
}}}

We distribute our Kerberos configuration via DNS, so it is very important that we do not "hardwire" the settings on any of the servers (except the KDCs themselves).  If we did, we wouldn't notice at first, but strange problems would crop up as soon as the DNS settings were changed.  So, it is important that we put only the bare minimum amount of information in {{{krb5.conf}}}.


=== 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-afs}}} package lets linux use the AFS user database (the {{{ptserver}}} or protection server) as a name service and 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:  afs files
group:   afs files
shadow:      files
}}}

Then put the following lines in {{{/etc/default/ptdbnssd}}}:

{{{
HOMEDIRS='prefix'
SHELLS='user'
}}}

And restart the daemon:

{{{
/etc/init.d/libnssptdbd restart
}}}


=== Install Name Service Caching Daemon ===

Our version of {{{libnss-ptdb}}} is configured to do no caching.  Therefore, to get acceptable performance, we need to run {{{nscd}}}.

{{{
  apt-get install nscd
}}}

=== 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)

Here's the usual PAM setup:

/etc/pam.d/common-account:

{{{
account sufficient        pam_unix.so
account required        pam_ldap.so
account required        pam_krb5.so debug

# temporary line for emergencies
#account required        pam_unix.so

account required pam_access.so
account    requisite    pam_listfile.so item=user sense=allow file=/etc/login.restrict onerr=succeed
}}}

/etc/pam.d/common-auth:

{{{
auth    sufficient        pam_krb5.so debug forwardable ignore_root
auth    optional          pam_afs_session.so program=/usr/bin/aklog debug
auth    required          pam_unix.so nullok_secure try_first_pass use_authtok

# temporary line for emergencies
#auth    required          pam_unix.so nullok_secure

auth    required          pam_env.so
auth       requisite    pam_listfile.so item=user sense=allow file=/etc/login.restrict onerr=succeed
}}}

/etc/pam.d/common-password:

{{{
password sufficient pam_krb5.so 
password required   pam_unix.so nullok obscure min=4 max=8 md5 shadow try_first_pass
}}}

/etc/pam.d/common-session:

{{{
session requisite pam_limits.so
session required  pam_unix_session.so      # Unix module just logs access
session optional  pam_krb5.so
session optional  pam_afs_session.so program=/usr/bin/aklog debug
}}}

/etc/pam.d/ssh

{{{
# sshd is stupid and does not consult the "auth" section of pam
# when GssapiAuthentication=yes, even if UsePAM=yes.  Retarded.
# Therefore, we add the check to the "account" section as well.
account    requisite    pam_listfile.so item=user sense=allow file=/etc/login.restrict onerr=succeed
auth       requisite    pam_listfile.so item=user sense=allow file=/etc/login.restrict onerr=succeed
}}}

If the machine is intended for user logins, DO NOT create /etc/login.restrict. If the machine is only
intended for admin logins, then create the file /etc/login.restrict with the following contents:

{{{
adamc_admin
docelic_admin
megacz_admin
mwolson_admin
ntk_admin
}}}

=== Configure SSH ===

==== Configure SSH Client ====

Insert these lines in {{{/etc/ssh/ssh_config}}} so that ''outbound'' ssh connections will always try to use Kerberos if available:

{{{
  Host *
    GSSAPIAuthentication yes
    GSSAPIDelegateCredentials no
}}}

==== Configure SSH Server ====


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
}}}

=== Populate sudoers ===

Don't forget to give all of the admins lines in {{{/etc/sudoers}}}.

=== 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.

==== ssmtp ====

Life is simpler when you run {{{ssmtp}}}.  You can direct the mail stream either to {{{deleuze}}} (preferred) or to a copy of {{{exim}}} running locally (but why bother running it?).