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

List the Machine on the Wiki

The hostname of the machine should be decided through a Members Poll (accessible from members portal) such as https://members.hcoop.net/portal/poll?id=31.

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.

Add the machine to the IpAddresses page.

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.

If there's _anything_ server-specific, please add an entry under "Specific Machines" on page AdminArea and document what it is. Rebooting procedures are an ideal candidate for this.

Add a DNS entry for the server

This is done as follows:

1. Edit /afs/hcoop.net/common/etc/domtool/lib/hcoop.dtl and add definition for "HOSTNAME_ip" (search for "deleuze_ip" and just copy the line to new name)

2. Edit /afs/hcoop.net/user/h/hc/hcoop/.domtool/hcoop.net to add the new DNS entry, using HOSTNAME_ip (again, can use deleuze_ip as example)

3. To apply DomTool configuration, run DOMTOOL_USER=hcoop domtool hcoop.net in the ~hcoop/.domtool/ directory

4. Using the peer1 request portal, add a reverse dns mapping to the hostname

Install Debian

We use Debian GNU.

Here are the installation notes to help you:

1. Find Debian stable image (whichever is 'stable' at time of installation -- this documentation is written for Squeeze)
2. Prepare a USB stick to boot from (can do it manually or with convenient tool called "unetbootin")
3. In system BIOS, choose 'Auto-power on on power restore' (if there is such option), and see if you can make USB stick to not be the first disk (when it's the first disk, it gets assigned device name /dev/sda and makes the installation a tiny bit harder)

4. See which network card is in the server, if it requires non-free firmware, the package needs to be manually copied from Debian's non-free repository onto the install media (example is package "firmware-bnx2" for Broadcom NetXtremeII cards (http://packages.debian.org/sid/all/firmware-bnx2/download)). Once package is on the media, the install procedure will, if it is needed, automatically find and install it

5. For timezone, use timezone where the server is physically located, and answer Yes to "Is the hardware clock set to GMT?"

6. Choose manual network configuration, specifying the choosen hostname, IP and network details as listed on the IpAddresses page

7. Partition disks. Most often, this comes town to creating identical partitions on all disks that are part of RAID1, and creating RAID arrays as in the example that follows. Currently, we usually configure: all remaining free space on /, /boot (300M), /var/cache/openafs (set to 5 or more GB), /tmp (1G), and installer suggested amount of swap.

   Example: 2x 160 GB system disks
   
   System disk 1:
   
   sda1: primary, beginning, 1 GB, ext3, /boot
   sda2: primary, beginning, 8 GB, use as phys. volume for RAID (swap space: 1 GB x number of proc. cores)
   sda3: primary, beginning, all available space, use as phys. volume for RAID
   
   System disk 2:
   
   sdb1: primary, beginning, 1 GB, ext3, unmounted
   sdb2: primary, beginning, 8 GB, use as phys. volume for RAID (swap, same size as above)
   sdb3: primary, beginning, all available space, use as phys. volume for RAID
   
   Then, after RAID partitions have been assigned, new option "Configure RAID"
   will appear at the top of the partitioning menu. We add the two devices in
   RAID 1 mode:
   
   md0: sda2 and sdb2
   md1: sda3 and sdb3
   
   Then, they appear in the partitions list and are configured as follows:
   
   md0: swap
   md1: ext3, /

8. Users & password setup: set root password, and create "root0" with a unique password (the installer forces at least one user account, make sure to delete the account after installation)

9. If /dev/sda is the USB stick and not the first disk, do not install GRUB to the Master Boot Record of /dev/sda. Instead, answer No at the prompt and choose /dev/sdb as the device. Then, take USB stick out, edit /boot/grub/menu.lst to replace references to hd(1,0) with hd(0,0), run update-grub.conf and grub-install /dev/sdb. No other tunings (to /etc/fstab or mdadm.conf) are needed as, if you used the partitioning example, no direct partitions occur in fstab, and for mdadm -- it uses UUIDs instead of partition names anyway.

10. In tasksel, at the end of installation, select "Standard system utilities" and "OpenSSH server"

Booting into the new machine

When the machine boots for the first time, run:

dpkg-reconfigure debconf    # (choose interface: Dialog, priority: Low).

apt-get install less sudo vim emacs23-nox etckeeper changetrack lm-sensors openssh-server debsums logcheck bzip2 denyhosts rkhunter

Verify that disks performance is as expected using sync; sync; hdparm -tT /dev/sdX.

Activate etckeeper as documented on EtcKeeper.

Edit /etc/default/changetrack and set AUTO_TRACK_ALL_CONFFILES=yes.

Edit /etc/tripwire/twcfg.txt and set MAILNOVIOLATIONS =false. Initialize the database with tripwire --init. (If tripwire is installed)

Edit /etc/aliases and set "root" alias to "logs@hcoop.net", and possibly other addresses, separated by commas. (logs@ is an aliasMulti, defined in ~hcoop/.domtool/hcoop.net and lists people who want to receive verbose system logs).

Run sensors-detect to see if the kernel has appropriate thermal modules for the server, and add any drivers detected to /etc/modules.

For all ext partitions, run tune2fs -j -c0 -i0 /dev/sdXX (and /dev/mdX for RAID arrays).

Tune the /etc/apt/sources.list

cat > /etc/apt/sources.list <<\EOF
deb http://mirror.peer1.net/debian/ squeeze main
deb-src http://mirror.peer1.net/debian/ squeeze main

deb http://security.debian.org/ squeeze/updates main
deb-src http://security.debian.org/ squeeze/updates main

# backports are fairly useful and not installed by default
deb http://backports.debian.org/debian-backports squeeze-backports main
deb-src http://backports.debian.org/debian-backports squeeze-backports main
EOF

apt-get update
apt-get dist-upgrade

Install the AFS Client

The AFS client gets very unhappy if the partition holding /var/cache/openafs fills up. To ensure that this can't happen, we'll create a 2GB file and mount it there using the loopback device. This gives the openafs client a partition-in-a-file all to itself that no other process can interfere with.

First, create the file:

dd if=/dev/zero of=/var/cache/openafs.ext3 bs=1M count=2K
chmod go-rwx /var/cache/openafs.ext3
mke2fs -F /var/cache/openafs.ext3
tune2fs -j -i0 -c0 /var/cache/openafs.ext3

Then mount it.

Then, give our preferences to debconf:

debconf-set-selections <<\EOF
openafs-client openafs-client/thiscell string hcoop.net
openafs-client openafs-client/thiscell seen true
openafs-client openafs-client/dynroot boolean true
openafs-client openafs-client/dynroot seen true
openafs-client openafs-client/cachesize string 1500000
openafs-client openafs-client/cachesize seen true
openafs-client openafs-client/cell-info string
openafs-client openafs-client/cell-info seen true
openafs-client openafs-client/run-client boolean true
openafs-client openafs-client/run-client seen true
EOF

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

Install libnss-afs.

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. This step is not optional.

  apt-get install ntp

Configure Kerberos

VERY IMPORTANT: put exactly the following in /etc/krb5.conf -- no more, no less (or actually, look up how it's done on Fritz or Hopper).

[libdefaults]
        default_realm = HCOOP.NET
        kdc_timesync = 1
        forwardable = true
        proxiable = true
        rdns = no          # undocumented option to disable reverse DNS lookups
[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

afs is checked before files to keep UIDs consistent.

Install Name Service Caching Daemon

It is highly recommended to install nscd in order to get good performance out of libnss-afs.

  apt-get install nscd

We prefer to run nscd as a runit service so that it does not go down (except on deleuze, where it must be started strictly after AFS in the boot sequence).

  apt-get install runit
  mkdir /etc/service/nscd
  cat <<EOF > /etc/service/nscd/run
#!/bin/sh                                                                       
exec nscd -d
EOF
  mkdir /etc/service/nscd/log
  cat <<EOF > /etc/service/nscd/log/run
#!/bin/bash                                                                     
svlogd -tt /var/log/nscd/
EOF
  mkdir /var/log/nscd
  chmod +x /etc/service/nscd/log/run
  chmod +x /etc/service/nscd/run

  dpkg-divert --rename /etc/init.d/nscd
  ln -s /usr/bin/sv /etc/init.d/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

/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

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

auth    required          pam_env.so

/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/login (Add to beginning of file):

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

/etc/pam.d/ssh (Add just before @include common-auth line):

# sshd does not consult the "auth" section of pam when
# GssapiAuthentication=yes, even if UsePAM=yes.  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
clinton_admin
docelic_admin
rkd_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):

   REALM=HCOOP.NET
   ADMIN=myself_admin       # your admin username
   SERVER=server.hcoop.net
   rm -f /etc/krb5.keytab   # important -- if it already exists the new key will merely be appended
   kadmin -p $ADMIN@$REALM -r $REALM -q "add_principal -randkey host/$SERVER@$REALM" # unless it already exists (reinstall of VM for example)
   kadmin -p $ADMIN@$REALM -r $REALM -q "ktadd -k /etc/krb5.keytab host/$SERVER@$REALM"
   chown root:root /etc/krb5.keytab
   chmod go-rwx /etc/krb5.keytab

Then add these lines to the bottom of /etc/ssh/sshd_config:

  GssapiKeyExchange yes
  GssapiAuthentication yes
  GSSAPICleanupCredentials yes

Finally, restart the ssh server:

  /etc/init.d/ssh restart

Populate sudoers

Don't forget to give all of the admins lines in /etc/sudoers. Each line should look like:

  user_admin  ALL=(ALL) NOPASSWD: ALL

Set Up Some Cron Scripts

/etc/cron.daily/hcoop-clean-tmp:

#
# Clean /tmp periodically.
#
# Edit $TMPTIME in /etc/default/rcS to change the maximal age of /tmp entries
# before they are removed.

exec /afs/hcoop.net/common/etc/scripts/hcoop-clean-tmp

Optional Steps

Install commonly-used packages

apt-get install \
  xbase-clients       # provides xauth, without which "ssh -Y" will not work
  dpkg-dev-el         # provide debian-changelog-mode

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.

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.

Here are the instructions for configuring it. Make sure that bind9 (if running) is only listening to 127.0.0.1 and the public IP address of the machine. We tell dnscache to listen on 127.0.0.2 so as to avoid conflicts with bind.

  apt-get install djbdns

  # If needed:
  addgroup --system Gdnscache
  adduser --system Gdnscache --ingroup Gdnscache

  # Create /etc/service/dnscache
  dnscache-conf Gdnscache Gdnscache /etc/service/dnscache 127.0.0.2

  # Change default listen address 127.0.0.1 to .2
  perl -pi -e 's/\.1/.2/' /etc/service/dnscache/env/IP

  # Let dnscache answer queries only from 127.0.0.2
  mv /var/dnscache/root/ip/127.0.0.1 /var/dnscache/root/ip/127.0.0.2

  sv restart dnscache

Then modify /etc/resolv.conf, replacing the nameserver lines with:

nameserver 127.0.0.2

/etc/hosts

If not present already:

echo '127.0.0.1 localhost' > /etc/hosts

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?).

Be sure to enable FromLineOverride, which ships defaulted to "off" in Debian.

apt-get install ssmtp
sed -i 's_FromLineOverride.*_FromLineOverride=YES_' /etc/ssmtp/ssmtp.conf

noatime

By default, Linux will write to the disk in order to update the atime ("access time") every time a file is read from; this substantially degrades performance. You can disable this behavior by editing /etc/fstab

# <file system> <mount point>   <type>  <options>                          <dump>  <pass>
/dev/hda1       /               ext3    defaults,noatime,errors=remount-ro 0       1

This is especially important on filesystems which are used to store AFS volumes.

etckeeper

apt-get install etckeeper
cd /etc
etckeeper init
etckeeper commit "Initial checkin"
git gc

nitpicks

1. Debian's installer seems to want to put an entry for the machine's own hostname in /etc/hosts, resolving to 127.0.0.1. You'll probably want to remove it.

---

CategorySystemAdministration CategoryHistorical