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| 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. === Out Of Band Access === |
#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 === |
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| 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. |
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| We use Debian. Install it. === Kernel Compilation === |
We use Debian. Install it. We should put our standard {{{/etc/apt/sources.list}}} here. === Compile a Kernel === |
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| === AFS Client === 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: {{{ apt-get install krb5-user libkrb5-dev |
=== 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 sudo \ module-assistant build-essential bison flex debhelper # required in order to build the module |
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| openafs-dbg*.deb \ | |
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| Also be sure to {{{ apt-get install module-assistant build-essential module-init-tools }}} |
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| Do this and check that /afs shows up. === Install AFS Extras === Now that afs is up, you can easily: {{{ dpkg -i /afs/hcoop.net/common/debian/libnss-ptdb/*.deb |
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 |
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| 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}}}"). === 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. === /etc/krb5.conf === 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. === configuring libnss-ptdb === 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: 1. the userid for a given username 2. the username for a userid |
dpkg -i /afs/megacz.com/debian/fsr*.deb (cd /afs/megacz.com/debian/krb5-user; dpkg -i krb5-user*.deb libkrb53*.deb libkadm*.deb libkrb5-dev*) }}} The first three packages are explained below; the fourth one is the {{{fsr}}} command (recursive "{{{fs}}}"). The last line installs a fixed version of kadmin which understands DNS entries. === 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 |
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| 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 }}} === configuring pam === PAM is the mechanism used by Linux to do the following: |
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 }}} === 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: |
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| 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. === configuring ssh to get tokens+tickets === |
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 # 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 ==== |
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| Add this principal to the KDC like this (execute these commands on the new server, as root, while holding admin tokens): {{{ kadmin -r HCOOP.NET ank -randkey host/server.hcoop.net@HCOOP.NET ktadd -k /etc/krb5.keytab quit |
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 $REALM -q "ank -randkey host/$SERVER@$REALM" kadmin -p $ADMIN@$REALM -r $REALM -q "ktadd -k /etc/krb5.keytab host/$SERVER@$REALM" |
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| Then these lines to /etc/ssh/sshd_config: | Then add these lines to the bottom of {{{/etc/ssh/sshd_config}}}: |
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| GSSAPICleanupCredentials no UsePAM yes }}} |
GSSAPICleanupCredentials yes }}} === Populate sudoers === Don't forget to give all of the admins lines in {{{/etc/sudoers}}}. Each line should look like: {{{ user_admin ALL=(ALL) NOPASSWD: ALL }}} === Optional Steps === ==== Performance-Tune the OpenAFS Client ==== FIXME: AdamM needs to fill this in ==== runit ==== The runit package is a mechanism for starting, stopping, and monitoring daemons. It is an alternative to the traditional {{{/etc/init.d}}} and {{{start-stop-daemon}}} scheme. Its chief advantages are: 1. It launches daemons with '''clean process state'''; the daemon inherits nothing from the administrator invoking the start/stop command because the daemon is not forked as a child of the administrator's shell (rather, a request is sent {{{runit}}} daemon asking it to fork the daemon). This is very important when dealing with tokens and pags. 2. Runit monitors the processes that it forks, and restarts them if they die. 3. Runit eliminates the need for pidfiles and the associated risk of starting multiple copies of a daemon. 4. Runit captures the daemon's {{{stdout}}} and either sends it to a logger (if specified) or else displays it in the process name (output of {{{ps}}}) {{{ apt-get install runit }}} When you move a process from {{{/etc/init.d/}}} control to {{{runit}}} supervision, you should inform debian that you have done so: {{{ # assuming /var/service/$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?). |
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
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:
- Keyboard access
- Screen access
- 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 sudo \
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-packagesOnce 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 (cd /afs/megacz.com/debian/krb5-user; dpkg -i krb5-user*.deb libkrb53*.deb libkadm*.deb libkrb5-dev*)
The first three packages are explained below; the fourth one is the fsr command (recursive "fs"). The last line installs a fixed version of kadmin which understands DNS entries.
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/2We 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:
- the userid for a given username and vice versa
- the groupid for a given groupname and vice versa
- the home directory for a user
- the shell for a user
- 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
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:
- decide if somebody is who they say they are (authentication; in our case via kerberos)
set up sessions (in the case of AFS, this means creating PAGs)
- 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 # 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):
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 $REALM -q "ank -randkey host/$SERVER@$REALM" kadmin -p $ADMIN@$REALM -r $REALM -q "ktadd -k /etc/krb5.keytab host/$SERVER@$REALM" chown root:root /etc/krb5.keytab chmod go-rwx /etc/krb5.keytab
Then add these lines to the bottom of /etc/ssh/sshd_config:
GssapiKeyExchange yes GssapiAuthentication yes GSSAPICleanupCredentials yes
Populate sudoers
Don't forget to give all of the admins lines in /etc/sudoers. Each line should look like:
user_admin ALL=(ALL) NOPASSWD: ALL
Optional Steps
Performance-Tune the OpenAFS Client
FIXME: AdamM needs to fill this in
runit
The runit package is a mechanism for starting, stopping, and monitoring daemons. It is an alternative to the traditional /etc/init.d and start-stop-daemon scheme. Its chief advantages are:
It launches daemons with clean process state; the daemon inherits nothing from the administrator invoking the start/stop command because the daemon is not forked as a child of the administrator's shell (rather, a request is sent runit daemon asking it to fork the daemon). This is very important when dealing with tokens and pags.
- Runit monitors the processes that it forks, and restarts them if they die.
- Runit eliminates the need for pidfiles and the associated risk of starting multiple copies of a daemon.
Runit captures the daemon's stdout and either sends it to a logger (if specified) or else displays it in the process name (output of ps)
apt-get install runit
When you move a process from /etc/init.d/ control to runit supervision, you should inform debian that you have done so:
# assuming /var/service/$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?).