Upgrade des Debian Edu Haupt-Servers (TJENER) von Debian Edu squeeze nach Debian Edu jessie

Services on TJENER

The following services / features on TJENER must be functional:

• LDAP
• Apache2
  • GOsa²
  • Nagios3
  • Munin
• DNS
• DHCP
• Samba
• Squid3
• Debian PXE Installer
• Exim4
  • lokale Mailzustellung von TJENER an TJENER
  • Netzwerk-Mailzustellung von Edu Clients an TJENER
• Dovecot
  • Zugriff via Mail-Client (IMAPS)
• ...

Preparations

• Perform a manual dump of your LDAP database (in case things fail on the way):

  root@tjener:~# slapcat > /root/slapcat-$(date +%Y%m%d%H%M%S).ldif

• Backup the complete TJENER system (so that you can completely restore the old state from backup, if needed).

• Backup the /etc/ configuration files and have them at hand when fixing various service settings once packages have been upgraded to Debian jessie state.

Package Upgrades

to Debian (Edu) wheezy

• Update /etc/apt/sources.list and individual configurations in /etc/apt/sources.list.d/, so that packages for Debian wheezy will get installed with next upgrade / dist-upgrade.

• Run upgrade and dist-upgrade in two steps

  root@tjener:~# apt-get upgrade
  root@tjener:~# apt-get dist-upgrade

• Reboot into the new Debian wheezy system, ignore if some services are broken / non-functional.

to Debian (Edu) jessie

• Update /etc/apt/sources.list and individual configurations in /etc/apt/sources.list.d/, so that packages for Debian jessie will get installed with next upgrade / dist-upgrade.

• Run upgrade and dist-upgrade in two steps

  root@tjener:~# apt-get upgrade
  root@tjener:~# apt-get dist-upgrade

• Reboot into the new Debian jessie system, ignore if some services are broken / non-functional.

Possible mistakes

• Don't forget the reboot into the Debian wheezy system, because you will run into troubles when upgrading the udev package from wheezy to jessie if still running the 2.6.32 Linux kernel from Debian squeeze.

Update command-not-found database

Make sure that the command-not-found tool is aware of commands/applications available in Debian jessie:

root@tjener:~# update-command-not-found

Fixing the TJENER setup after package upgrade

The Debian Edu mainserver is not easily upgradable, because the mainserver installation process in Debian Edu does many modifications to the plain Debian system.

Fix UDP checksumming when on KVM (virtio_net)

If the Debian Edu mainserver TJENER runs in KVM and uses the virtio_net driver, you may want to disable checksum off-loading (see [1] and [2] for details):

auto eth0
iface eth0 inet static
    address 10.0.2.2
    netmask 255.0.0.0
    broadcast 10.255.255.255
    gateway 10.0.0.1
    # disable checksum off-loading
    pre-up ethtool -K eth0 tx off

Alternatively, use the e1000 driver / virtual NIC in KVM.

Note: Disabling checksum off-loading is especially important for machines running isc-dhcp-server, but you should consider it helpful (or switching to e1000) for all KVM instances.

Fix DNS server (bind9)

During the upgrade process, the DNS server configuration (synced into text files from LDAP) gets lost. You need to rebuild the DNS server configuration files from LDAP manually.

• Add

  10.0.2.2 ldap.intern

  to /etc/hosts temporarily.

• Add

  BIND_DATA="/etc/bind"

  at the end of /etc/default/ldap2zone.

• Rebuild the DNS configuration (in /etc/bind) via ldap2bind command:

  root@tjener:~# su -s /bin/bash - bind
  bind@tjener:~$ PATH=/sbin:/bin:/usr/sbin:/usr/bin /usr/sbin/ldap2bind

Fix Apache2 Setup

The next step is getting the Apache2 setup fixed, so you can regain access to GOsa² installed on TJENER:

• Remove dangling symlinks in /etc/apache2/sites-enabled related to Debian Edu

  root@tjener:~# rm -f /etc/apache2/sites-enabled/debian-edu-*default

• Create proper symlinks (having a trainling .conf in the symlink name via the a2ensite utility:

  root@tjener:~# a2ensite debian-edu-default
  root@tjener:~# a2ensite debian-edu-ssl-default

• Don't forget to restart Apache2:

  root@tjener:~# invoke-rc.d apache2 restart

Fix GOsa² binding to LDAP

Once Apache2 is up-and-running again, you may want to access GOsa² to check if your LDAP tree is still in shape after upgrade (it surely will be). However, access GOsa² results in this message after a fresh squeeze to jessie Upgrade:

<b>Schwerer Fehler</b>
Fehler beim Verbinden mit dem LDAP-Server: Could not bind to cn=gosa-admin,ou=ldap-access,dc=skole,dc=skolelinux,dc=no (während der Arbeit auf LDAP-Server 'ldap://ldap.intern')

Bitte beheben Sie obigen Fehler und laden die Seite neu. 

Two steps are required to get this issue fixed:

• Fix /etc/gosa/gosa.secrets with this command

  root@tjener:~# sed -e 's/GOSA_KEY/GOSAKEY/g' -i /etc/gosa/gosa.secrets

• Fix /etc/gosa/gosa.conf manually after upgrade. In your new (i.e., jessie'ish) gosa.conf file you are likely to find $GOSAPWD as adminPassword and snapshotAdminPassword values. This, of course is wrong, the $GOSAPWD variable is only used while boot-strapping the Debian Edu mainserver at installation time. Steps to get this variable replaced by the original hashed password string:

  • Get /etc/gosa/gosa.conf from your earlier taken configuration backup

  • Search for the string "adminPassword" in the configuration and obtain the hash referenced there as a value

  • Replace $GOSAPWD by that hash:

    root@tjener:~# sed -e 's/$GOSAPWD/<put-your-pw-hash-here/g' -i /etc/gosa/gosa.conf

• Don't forget to restart Apache2 (as /etc/gosa/gosa.secrets gets pulled in into the Apache2 runtime configuration).

• Test GOsa² access:

  • Open this URL in your webbrowser: https://www/gosa/

  • Login with any of your LDAP accounts

Install missing GOsa² packages

On one migration we had to post-upgrade install the package gosa-plugin-goto:

root@tjener:~# apt-get install gosa-plugin-goto

(Re-)Enable GOsa² Apache2 configuration

It may happen that GOsa²'s Apache2 configuration is not enabled anymore after dist-upgrade (observed during the step from wheezy to jessie). Re-enabling is simple:

root@tjener:~# a2enconf gosa && invoke-rc.d apache2 restart

Set magic gosa.conf Version String

After some upgrades of the package gosa the following can be observed: If the package maintainer has modified the default gosa.conf file shipped with the gosa package, a site admin will see this warning message when logging into GOsa after the upgrade: The configuration file you are using is outdated. Please move the GOsa configuration file away to run the GOsa setup again. (German: Die von Ihnen verwendete Konfigurationsdatei scheint veraltet zu sein. Bitte entfernen Sie diese Datei und starten Sie das GOsa-Setup erneut).

This can and should be fixed by setting a magic version hash in /etc/gosa/gosa.conf:

root@tjener:/etc/gosa# diff -ur /etc/gosa/gosa.conf.orig /etc/gosa/gosa.conf
--- /etc/gosa/gosa.conf.orig    2015-10-31 09:46:14.000000000 +0100
+++ /etc/gosa/gosa.conf 2015-10-31 09:46:28.000000000 +0100
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<conf configVersion="0e16844ac91297ffc1dee2f0f65ef2af">
+<conf configVersion="Managed-by-Debian-Edu">
 
   <!-- GOsa menu definition **************************************************

(Re-)Enable SLBackup Apache2 configuration

It may happen that SLBackup's Apache2 configuration is not enabled anymore after dist-upgrade (observed during the step from wheezy to jessie). Re-enabling is simple:

root@tjener:~# a2enconf slbackup-php && invoke-rc.d apache2 restart

Reactivate libpam-krb5 configuration

By some reason, the pam_krb5.so configuration is not active anymore after upgrade from wheezy to jessie. Simplest way for re-enabling it:

root@tjener:~# apt-get install --reinstall libpam-krb5

Update LDAP DIT for Debian Edu jessie

There are some variables ($GOSAADMINSDN64, $TEACHERSDN64, etc.) in the below LDAP diff. The "64" denotes that you need to use the base64 encoded representation of the DN. You will find those base64 encoded strings in the LDAP tree, but you can also create them manually.

$ echo "cn=gosa-admin,ou=ldap-access,dc=skole,dc=skolelinux,dc=no" | base64

Use the ldapvi tool to add the below information to the Debian Edu mainserver's LDAP tree.

diff --git a/ldap-bootstrap/autofs.ldif b/ldap-bootstrap/autofs.ldif
index 9d68cbc..05fe3e0 100644
--- a/ldap-bootstrap/autofs.ldif
+++ b/ldap-bootstrap/autofs.ldif
@@ -40,4 +40,4 @@ ou: auto.tjener
 dn: cn=/,ou=auto.tjener,ou=automount,dc=skole,dc=skolelinux,dc=no
 objectClass: automount
 cn: /
-automountInformation: -fstype=nfs4,tcp,rsize=32768,wsize=32768,rw,intr,hard,nodev,nosuid tjener.intern:/&
+automountInformation: -fstype=nfs4,sec=sys,tcp,rw,intr,hard,nodev,nosuid tjener.intern:/&
diff --git a/ldap-bootstrap/gosa-server.ldif b/ldap-bootstrap/gosa-server.ldif
index 102c86a..46f5098 100644
--- a/ldap-bootstrap/gosa-server.ldif
+++ b/ldap-bootstrap/gosa-server.ldif
@@ -6,12 +6,16 @@ ou: servers
 
 dn: cn=tjener,ou=servers,ou=systems,dc=skole,dc=skolelinux,dc=no
 macAddress: $MAC
+description: Main server; modify only if 100% sure.
 objectClass: top
 objectClass: GOhard
 objectClass: goServer
 objectClass: dhcpServer
+objectClass: goNtpServer
+objectClass: goLdapServer
 cn: tjener
 dhcpServiceDN: cn=dhcp,cn=tjener,ou=servers,ou=systems,dc=skole,dc=skolelinux,dc=no
+goLdapBase: ldap://tjener:389/dc=skole,dc=skolelinux,dc=no
 ipHostNumber: 10.0.2.2
 gotoMode: locked
 
@@ -245,7 +249,7 @@ dhcpRange: 10.0.16.20 10.0.31.254
 # subnet00.intern shared network
 dn: cn=subnet00.intern,cn=dhcp,cn=tjener,ou=servers,ou=systems,dc=skole,dc=skolelinux,dc=no
 dhcpOption: routers ltspserver00.subnet00
-dhcpOption: domain-name "intern subnet00.intern"
+dhcpOption: domain-name "intern"
 dhcpOption: subnet-mask 255.255.255.0
 dhcpOption: broadcast-address 192.168.0.255
 dhcpOption: root-path "/opt/ltsp/i386"
@@ -277,7 +281,7 @@ dhcpRange: 192.168.0.20 192.168.0.253
 # subnet01.intern shared network
 dn: cn=subnet01.intern,cn=dhcp,cn=tjener,ou=servers,ou=systems,dc=skole,dc=skolelinux,dc=no
 dhcpOption: routers ltspserver01.subnet01
-dhcpOption: domain-name "intern subnet01.intern"
+dhcpOption: domain-name "intern"
 dhcpOption: subnet-mask 255.255.255.0
 dhcpOption: broadcast-address 192.168.1.255
 dhcpOption: root-path "/opt/ltsp/i386"
diff --git a/ldap-bootstrap/gosa.ldif b/ldap-bootstrap/gosa.ldif
index 41bb76f..70a5afe 100644
--- a/ldap-bootstrap/gosa.ldif
+++ b/ldap-bootstrap/gosa.ldif
@@ -21,6 +21,11 @@ dn: ou=gosa,ou=configs,ou=systems,dc=skole,dc=skolelinux,dc=no
 objectClass: organizationalUnit
 ou: gosa
 
+dn: cn=netgroupSystem,ou=gosa,ou=configs,ou=systems,dc=skole,dc=skolelinux,dc=no
+cn: netgroupSystem
+objectClass: top
+objectClass: gosaConfig
+gosaSetting: netgroupSystemRDN:ou=netgroup
 ###################### Teachers #########################
 
@@ -191,13 +196,13 @@ dn: cn=admin-role,ou=aclroles,dc=skole,dc=skolelinux,dc=no
 objectClass: top
 objectClass: gosaRole
 gosaAclTemplate: 0:psub::all;cmdrw
-description: unlimited administrative permissions
+description: nearly unlimited administrative permissions
 cn: admin-role
 
 dn: cn=jradmin-role,ou=aclroles,dc=skole,dc=skolelinux,dc=no
 objectClass: top
 objectClass: gosaRole
-gosaAclTemplate: 0:sub::users/user;cmdrw,users/password;rw,users/posixAccount;r,groups/group;cmdr#description;w#memberUid;rw
+gosaAclTemplate: 0:sub::users/user;cmdrw,users/password;rw,users/posixAccount;r,users/sambaAccount;r,groups/group;cmdr#description;w#memberUid;rw
 description: limited administrative permissions
 cn: jradmin-role
 
diff --git a/ldap-bootstrap/ltsp.ldif b/ldap-bootstrap/ltsp.ldif
index 55e46f8..8fc0609 100644
--- a/ldap-bootstrap/ltsp.ldif
+++ b/ldap-bootstrap/ltsp.ldif
@@ -7,4 +7,4 @@ dn: cn=ltspConfigDefault,ou=ltsp,dc=skole,dc=skolelinux,dc=no
 objectclass: ltspClientConfig
 cn: ltspConfigDefault
 ltspConfig: NBD_SWAP=Y
-ltspConfig: SCREEN_07=ldm
+ltspConfig: KEEP_SYSTEM_SERVICES=lightdm
diff --git a/ldap-bootstrap/root.ldif b/ldap-bootstrap/root.ldif
index 2b41253..521c0ae 100644
--- a/ldap-bootstrap/root.ldif
+++ b/ldap-bootstrap/root.ldif
@@ -29,7 +29,7 @@ dc: skole
 ou: skole
 o: skole.skolelinux.no
 labeledURI: http://www/ LDAP for Debian Edu/Skolelinux
-gosaAclEntry: 0:psub:$GOSAADMINSDN64:server/servgeneric;#gotoMode;r#userPassword;r#FAIstate;r,all;cmdrw
+gosaAclEntry: 0:psub:$GOSAADMINSDN64:all;cmdrw,department/department;cmdrw,department/domain;r,department/organization;r,department/dcObject;r,department/country;r,department/DynamicLdapGroup;r,users/posixAccount;#shadowLastChange;r#gotoLastSystemLogin;r#mustchangepassword;r#shadowMin;r#shadowMax;r#shadowWarning;r#shadowInactive;r#shadowExpire;r#sshPublicKey;r#accessTo;r,users/sambaAccount;#AllowLoginOnTerminalServer;r#InheritClientConfig;r#sambaKickoffTime;r#enforcePasswordChange;r#cannotChangePassword;r#noPasswordRequired;r#passwordNeverExpires;r#temporaryDisabled;r#sambaLogonHours;r#sambaUserWorkstations;r
 gosaAclEntry: 1:psub:$TEACHERSDN64:users/user;r
 gosaAclEntry: 2:psub:Kg==:users/user;sr#personalTitle;w#academicTitle;w#dateOfBirth;w#gender;w#preferredLanguage;w#userPicture;w#homePostalAddress;w#homePhone;w#labeledURI;w,users/password;srw
 gosaAclEntry: 3:role:$ADMINROLEDN64:
@@ -50,6 +50,18 @@ objectClass: top
 objectClass: organizationalUnit
 ou: systems
 
+dn: ou=workstations,ou=systems,dc=skole,dc=skolelinux,dc=no
+objectClass: organizationalUnit
+ou: workstations
+
+dn: ou=terminals,ou=systems,dc=skole,dc=skolelinux,dc=no
+objectClass: organizationalUnit
+ou: terminals
+
+dn: ou=printers,ou=systems,dc=skole,dc=skolelinux,dc=no
+objectClass: organizationalUnit
+ou: printers
+
 dn: ou=winstations,ou=systems,dc=skole,dc=skolelinux,dc=no
 objectClass: top
 objectClass: organizationalUnit

NSCD and Netgroups

Until Debian bugs #793649, #800523 and #737079are not fixed in NSCD, we have to disabled netgroup caching via NSCD completely:

root@tjener:~# diff -u /etc/nscd.conf.orig  /etc/nscd.conf
--- /etc/nscd.conf.orig 2015-10-31 08:34:23.000000000 +0100
+++ /etc/nscd.conf      2015-10-31 08:34:38.000000000 +0100
@@ -78,7 +78,7 @@
        shared                  services        yes
        max-db-size             services        33554432
 
-       enable-cache            netgroup        yes
+       enable-cache            netgroup        no      
        positive-time-to-live   netgroup        28800
        negative-time-to-live   netgroup        20
        suggested-size          netgroup        211

Then restart NSCD and remove the stray netgroup cache file:

root@tjener:~# invoke-rc.d nscd restart
root@tjener:~# rm -f /var/cache/nscd/netgroup

Fix PXE Netinstall

On a Debian Edu network, you can install other Debian Edu machines via the Debian Edu main server by simply PXE booting a new machine.

Steps to get PXE Netinstall updated to Debian Edu jessie 8:

1. Clean-up old Debian Installer versions:

   # Debian Installer for Debian 7 (aka wheezy)
   root@tjener:~# apt-get remove --purge debian-installer-7.0-netboot-amd64 debian-installer-7.0-netboot-i386
   # Debian Installer for Debian 6 (aka squeeze) and before
   root@tjener:~# apt-get remove --purge debian-installer-6.0-netboot-amd64 debian-installer-6.0-netboot-i386

   The APT utility is likely to report about not being able to remove some of the package directories. This is caused by non-package files (e.g. initrd.gz backups) still remaining in those dirs. If that happens, remove those files and dirs manually.

2. Install the Debian Installer Netboot packages:

   root@tjener:~# apt-get install debian-installer-8-netboot-amd64 debian-installer-8-netboot-i386

3. Run the Debian Edu PXE Installer script:

   root@tjener:~# debian-edu-pxeinstall

4. Add non-free firmwares to your PXE based Debian Edu Installer:

   root@tjener:~# /usr/share/debian-edu-config/tools/pxe-addfirmware

Switch over to Squid3

In Debian Edu jessie, using the Squid http proxy server version 2 is deprecated. Instead, Squid version 3 gets used. We need to switch over to Debian package squid3 properly to make the upgraded main server resemble a freshly installed Debian Edu jessie main server:

• Install package squid3 first (while you still have a running squid (version 2) and stop it immediately:

  root@tjener:~# apt-get install squid3
  root@tjener:~# invoke-rc.d squid3 stop

• Now also stop the Squid v2 proxy server:

  root@tjener:~# invoke-rc.d squid stop

• Empty and unmount /var/spool/squid/:

  root@tjener:~# rm -Rf /var/spool/squid/*
  root@tjener:~# umount /var/spool/squid/

• Rename the underlying logical volume:

  root@tjener:~# lvrename /dev/vg_system/var+spool+squid /dev/vg_system/var+spool+squid3

• Check that /var/spool/squid3/ is (still) empty and mount the above logical volume to that directory:

  root@tjener:~# mount /dev/vg_system/var+spool+squid3 /var/spool/squid3

  Don't forget to adapt /etc/fstab accordingly.:

• Copy Debian Edu's squid.conf into the /etc/squid3/ folder:

  root@tjener:~# install -T -o root -g root -m 0644 /usr/share/debian-edu-config/squid3.conf /etc/squid3/squid-debian-edu.conf

• Tell Squid v3 to use the Debian Edu provided configuration file by creating /etc/default/squid3 by putting the below lines into that file:

  CONFIG=/etc/squid3/squid-debian-edu.conf
  SQUID_ARGS="-YC -f /etc/squid3/squid-debian-edu.conf"

• Make Squid v3 use 80% of the underlying spooling file systems:

  root@tjener:~# /usr/share/debian-edu-config/tools/squid-update-cachedir /etc/squid3/squid-debian-edu.conf

• Update system environment to the latest wpad.dat settings:

  root@tjener:~# /usr/share/debian-edu-config/tools/update-proxy-from-wpad /etc/debian-edu/www/wpad.dat

• Fully uninstall/purge the old Squid (v2) from the system:

  root@tjener:~# apt-get remove --purge squid

Fixing CUPS

Using Debian Edu's CUPS configuration file

You have to assure that Debian Edu's CUPS main configuration file gets used:

root@tjener:~# cd /etc/cups
root@tjener:~# cd mv cupsd.conf cupsd.conf.bak
root@tjener:~# ln -s cupsd-debian-edu.conf cupsd.conf

Note: If you have performed changes on Debian Edu's default cupsd-debian-edu.conf file, you may have to work-in those changes again (see: /etc/cups/cupsd-debian-edu.conf.dpkg-old or your backups for reference).

Allowing Debian Edu machines to browse CUPS daemon

The CUPS browsing is handled by the package cups-browsed}}. We observed distribution upgrades from squeeze to jessie where the {{{cups-browsed package was not installed after dist-upgrade. In such cases, install cups-browsed manually now:

root@tjener:~# apt-get install cups-browsed

Furthermore, you need package libnss-mdns installed for printer auto-discovery to work on multicast capable networks:

root@tjener:~# apt-get install libnss-mdns

CUPS in Debian jessie runs the browse daemon in a seprate process (cups-browsed). That daemon has its own configuration file (/etc/cups/cups-browsed.conf. Make sure that clients on the Debian Edu subnet can browse your print server's CUPS daemon by adding

BrowseAllow 10.0.0.0/8

to that configuration file.

If clients still cannot see the print server's printing devices, there may be issues on the client-side (e.g., package libnss-mdns is not installed there). Please see below.

Notes on Upgrading Debian Edu Clients

PAM Kerberos may be broken

On one system we encountered an issue where the file /usr/share/pam-configs/krb5 did not exist anymore after an upgrade/dist-upgrade from Debian squeeze to Debian jessie. The quick-fix for this is

root@<client>:~# apt-get install --reinstall libpam-krb5

Another issue is that cfEngine rules described in /etc/cfengine/debian-edu/cf.krb5client were not fully applied. The manual steps to (re-)apply those rules are:

root@<client>:~# ln -s /usr/share/debian-edu-config/pam-config-nopwdchange /usr/share/pam-configs/edu-nopwdchange
root@<client>:~# /usr/share/debian-edu-config/tools/sssd-generate-config -k > /etc/krb5.conf
root@<client>:~# /usr/sbin/pam-auth-update --package

CUPS Browsing

Please make sure that the packages cups-browsed and libnss-mdns are installed.

root@<client>:~# apt-get install cups-browsed libnss-mdns

After a little delay, all printers hosted on the Debian Edu print server (by default, this is tjener.intern) should appear under this browser URL on your client machine:

http://localhost:631

If this is not the case, you could try this work-around:

• Log into GOsa² and add a CNAME DNS alias to tjener.intern, named ipp.intern.

• Work-around on non-multicast capable networks: Add

  BrowsePoll ipp.intern

  to /etc/cups/cups-browsed.conf.

References

• [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=717215

• [2] https://forge.univention.org/bugzilla/show_bug.cgi?id=33160