Configuring clustered Samba: Difference between revisions
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= Goal = |
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= Setting up pCIFS using Samba and CTDB = |
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Configure clustered Samba using a CTDB cluster |
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As of April 2007 you can setup a simple Samba3 or Samba4 CTDB cluster, running either on loopback (with simulated nodes) or on a real cluster with TCP. This page will tell you how to get started. |
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= Note = |
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This page still contains some details not directly relevant to clustering Samba. The documentation is being cleaned up and restructured. |
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= Prerequisites = |
= Prerequisites = |
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* [[Basic CTDB configuration]] |
* [[Basic CTDB configuration]] |
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* [[Setting up a cluster filesystem]] |
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* [[Configuring the CTDB recovery lock]] (recommended) |
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* [[Adding public IP addresses]] (or some other failover/load balancing scheme) |
* [[Adding public IP addresses]] (or some other failover/load balancing scheme) |
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A clustered Samba install must set some specific configuration parameters |
A clustered Samba install must set some specific configuration parameters |
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netbios name = something |
netbios name = something |
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clustering = yes |
clustering = yes |
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idmap config * : backend = autorid |
idmap config * : backend = autorid |
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NB: |
NB: |
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* See [https://www.samba.org/samba/docs/man/manpages/idmap_autorid.8.html idmap(8)] for more information about the idmap configuration |
* See [https://www.samba.org/samba/docs/man/manpages/idmap_autorid.8.html idmap(8)] for more information about the idmap configuration |
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* netbios name should be the same on all |
* netbios name should be the same on all nodes |
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Note that <code>bind interfaces only = yes</code> should not be used when configuring clustered Samba with [[Adding public IP addresses|CTDB public IP addresses]]. CTDB will start <code>smbd</code> before public IP addresses are hosted, so <code>smbd</code> will not listen on any of the public IP addresses. When public IP addresses are eventually hosted, <code>smbd</code> will not bind to the new addresses. |
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If using the Samba registry then these must be set in smb.conf: |
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==Using the Samba registry== |
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include=registry |
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A recommended way of ensuring that all Samba nodes have the same configuration is to put most configuration into the registry. |
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= CTDB Configuration = |
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This means that <code>smb.conf</code> can be as simple as: |
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There are several things to configure in CTDB to support clustered Samba. |
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[global] |
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=== CTDB configuration file === |
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clustering = yes |
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include = registry |
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The initial contents of the registry can then be placed into a file (say <code>tmp.conf</code>): |
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The <code>CTDB_MANAGES_SAMBA</code> configuration variable must be set to <code>yes</code> in the [[Basic CTDB configuration#ctdbd configuration file|ctdbd configuration file]]. |
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[global] |
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For example: |
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security = ADS |
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logging = syslog |
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log level = 1 |
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netbios name = test |
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workgroup = SAMBA |
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realm = samba.example.com |
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idmap config * : backend = autorid |
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idmap config * : range = 1000000-1999999 |
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and loaded from one of the nodes: |
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CTDB_MANAGES_SAMBA=yes |
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net conf import tmp.conf |
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This causes CTDB to start and stop Samba at startup and shutdown. It also tells CTDB to monitor Samba. |
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Further <code>net conf</code> commands such as <code>net conf addshare</code> can then be used to continue configuration. |
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=== Recovery lock === |
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= Configure CTDB to manage Samba = |
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The recovery lock, configured via <code>CTDB_RECOVERY_LOCK</code> provides important split-brain prevention and is usually configured to point to a locl file in the cluster filesystem. See the RECOVERY LOCK section in [http://ctdb.samba.org/manpages/ctdb.7.html ctdb(7)] for more details. |
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For CTDB to manage Samba, the <code>50.samba</code> event script must be enabled |
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=== /etc/ctdb/events.d === |
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ctdb event script enable legacy 50.samba |
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This directory contains event scripts that are called out to by CTDB when certain events occur. Event scripts support health monitoring, service management, IP failover, internal CTDB operations and features. They handle events such as <code>startup</code>, <code>shutdown</code>, <code>monitor</code>, <code>releaseip</code> and <code>takeip</code>. |
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This causes CTDB to start and stop Samba at startup and shutdown. It also tells CTDB to monitor Samba. |
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Please see the service scripts that installed by ctdb in /etc/ctdb/events.d for examples of how to configure other services to be aware of the HA features of CTDB. |
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Similarly, if using <code>winbind</code>, CTDB should also be configured to manage it: |
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Also see /etc/ctdb/events.d/README for additional documentation on how to write and modify event scripts. |
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ctdb event script enable legacy 49.winbind |
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=== /etc/services === |
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Please see the <code>event</code> command in [http://ctdb.samba.org/manpages/ctdb.1.html ctdb(1)] for more details. |
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CTDB defaults to use IANA assigned TCP port 4379 for its traffic. |
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Configuring a different port to use for CTDB traffic is done by adding a ctdb entry to the /etc/services file. |
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CTDB will manage and start/stop/restart the Samba services, so the operating system should be configured so these are not started/stopped automatically. |
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Example: for change CTDB to use port 9999 add the following line to /etc/services |
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== Red Hat Linux variants == |
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ctdb 9999/tcp |
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If using a Red Hat Linux variant, the Samba services are <code>smb</code> and <code>winbind</code>. Starting them at boot time is not recommended and this can be disabled using <code>chkconfig</code>. |
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Note: all nodes in the cluster MUST use the same port or else CTDB will not start correctly. |
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chkconfig smb off |
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= Name resolution = |
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chkconfig winbind off |
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The service names and mechanism for disabling them varies across operating systems. |
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You need to setup some method for your Windows and NFS clients to find the nodes of the cluster, and automatically balance the load between the nodes. We recommend that you setup a round-robin DNS entry for your cluster, listing all the public IP addresses that CTDB will be managing as a single DNS A record. |
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= Event scripts = |
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You may also wish to setup a static WINS server entry listing all of your cluster nodes IP addresses. |
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= Managing Network Interfaces = |
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The default install of CTDB is able to add/remove IP addresses from your network interfaces using the CTDB_PUBLIC_ADDRESSS option shown above. |
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For more sophisticated interface management you will need to add a new events script in /etc/ctdb/events.d/. |
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For example, say you wanted CTDB to add a default route when it brings it up. You could have an event script called /etc/ctdb/events.d/11.route that looks like this: |
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#!/bin/sh |
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. /etc/ctdb/functions |
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loadconfig ctdb |
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cmd="$1" |
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shift |
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case $cmd in |
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takeip) |
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# we ignore errors from this, as the route might be up already when we're grabbing |
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# a 2nd IP on this interface |
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/sbin/ip route add $CTDB_PUBLIC_NETWORK via $CTDB_PUBLIC_GATEWAY dev $1 2> /dev/null |
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;; |
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esac |
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exit 0 |
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Then you would put CTDB_PUBLIC_NETWORK and CTDB_PUBLIC_GATEWAY in /etc/sysconfig/ctdb like this: |
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CTDB_PUBLIC_NETWORK="10.1.2.0/24" |
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CTDB_PUBLIC_GATEWAY="10.1.2.1" |
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CTDB clustering for Samba involves the <code>50.samba</code> and <code>49.winbind</code> event scripts. These are provided as part of CTDB and do not usually need to be changed. |
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There are several configuration variables that affect the operation of these scripts. Please see [http://ctdb.samba.org/manpages/ctdb-script.options.5.html ctdb-script.options(5)] for details. |
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= Filesystem specific configuration = |
= Filesystem specific configuration = |
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If you are interested in testing a new cluster filesystem with CTDB then we strongly recommend looking at the page on testing filesystems using [[ping_pong|ping_pong]] to ensure that the cluster filesystem supports correct POSIX locking semantics. |
If you are interested in testing a new cluster filesystem with CTDB then we strongly recommend looking at the page on testing filesystems using [[ping_pong|ping_pong]] to ensure that the cluster filesystem supports correct POSIX locking semantics. |
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== |
== IBM GPFS filesystem == |
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The GPFS filesystem ( |
The [https://www.ibm.com/support/knowledgecenter/SSFKCN/gpfs_welcome.html GPFS] filesystem (now known as [https://www-03.ibm.com/systems/storage/spectrum/scale/ Spectrum Scale ]) is a proprietary cluster filesystem that has been extensively tested with CTDB/Samba. When using GPFS, the following smb.conf settings are recommended |
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clustering = yes |
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idmap backend = tdb2 |
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fileid:mapping = fsname |
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vfs objects = gpfs fileid |
vfs objects = gpfs fileid |
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gpfs:sharemodes = No |
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gpfs:sharemodes = yes |
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fileid:algorithm = fsname |
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force unknown acl user = yes |
force unknown acl user = yes |
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nfs4: mode = special |
nfs4: mode = special |
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The ACL related options should only be enabled if you have NFSv4 ACLs enabled on your filesystem |
The ACL related options should only be enabled if you have NFSv4 ACLs enabled on your filesystem |
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The most important of these options is the "fileid: |
The most important of these options is the "fileid:algorithm". You risk data corruption if you use a different mapping backend with Samba and GPFS, because locking wilk break across nodes. NOTE: You must also load "fileid" as a vfs object in order for this to take effect. |
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A guide to configuring Samba with CTDB and GPFS can be found at [[Samba CTDB GPFS Cluster HowTo]] |
A guide to configuring Samba with CTDB and GPFS can be found at [[Samba CTDB GPFS Cluster HowTo]] |
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In comparison of Lustre configurating, setting up CTDB/Samba on the two different versions keeps the same way. The following settings are recommended: |
In comparison of Lustre configurating, setting up CTDB/Samba on the two different versions keeps the same way. The following settings are recommended: |
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vfs objects = fileid |
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clustering = yes |
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fileid:algorithm = fsname |
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idmap backend = tdb2 |
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fileid:mapping = fsname |
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use mmap = no |
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nt acl support = yes |
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ea support = yes |
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The options of "fileid:mapping |
The options of "fileid:mapping" must be specified to avoid possibe data corruption. |
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== GlusterFS filesystem == |
== GlusterFS filesystem == |
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recommended settings: |
recommended settings: |
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fileid:mapping = fsid |
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vfs objects = fileid |
vfs objects = fileid |
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fileid:algorithm = fsid |
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OCFS2 1.4 offers cluster-wide byte-range locking. |
OCFS2 1.4 offers cluster-wide byte-range locking. |
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= |
== Other cluster filesystems == |
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If you can't find documentation about your choice of cluster filesystem and clustered Samba then you might need to work around some limitations. |
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Just start the ctdb service on all nodes. A sample init script (works for RedHat) is located in /usr/src/ctdb/config/ctdb.init |
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=== Inconsistent device numbers === |
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If you have taken advantage of the ability of CTDB to start other services, then you should disable those other services with chkconfig, or your systems service configuration tool. Those services will instead be started by ctdb using the /etc/ctdb/events.d service scripts. |
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Locking will not work if a cluster filesystem does not provide uniform device numbers across nodes. It testing shows locking problems then you should test [[Setting_up_a_cluster_filesystem#Checking_uniformity_of_device_and_inode_numbering|device number uniformity]] of your cluster filesystem. |
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If you wish to cope with software faults in ctdb, or want ctdb to automatically restart when an administration kills it, then you may wish to add a cron entry for root like this: |
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To work around a lack of device number uniformity, the following settings should be used in the global section of the Samba configuration: |
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vfs objects = fileid |
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fileid:algorithm = fsname |
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See [https://www.samba.org/samba/docs/man/manpages/vfs_fileid.8.html vfs_fileid(8)] for more information. |
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* * * * * /etc/init.d/ctdb cron > /dev/null 2>&1 |
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= Testing |
= Testing clustered Samba = |
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Once your cluster is up and running, you may wish to know how to test that it is functioning correctly. The following tests may help with that |
Once your cluster is up and running, you may wish to know how to test that it is functioning correctly. The following tests may help with that |
Latest revision as of 15:59, 13 November 2023
Goal
Configure clustered Samba using a CTDB cluster
Note
This page still contains some details not directly relevant to clustering Samba. The documentation is being cleaned up and restructured.
Prerequisites
- Basic CTDB configuration
- Setting up a cluster filesystem
- Configuring the CTDB recovery lock (recommended)
- Adding public IP addresses (or some other failover/load balancing scheme)
Samba Configuration
Next you need to initialise the Samba password database, e.g.
smbpasswd -a root
Samba with clustering must use the tdbsam or ldap SAM passdb backends (it must not use the default smbpasswd backend), or must be configured to be a member of a domain. The rest of the configuration of Samba is exactly as it is done on a normal system. See the docs on http://samba.org/ for details.
Critical smb.conf parameters
A clustered Samba install must set some specific configuration parameters
netbios name = something clustering = yes idmap config * : backend = autorid idmap config * : range = 1000000-1999999
NB:
- See idmap(8) for more information about the idmap configuration
- netbios name should be the same on all nodes
Note that bind interfaces only = yes
should not be used when configuring clustered Samba with CTDB public IP addresses. CTDB will start smbd
before public IP addresses are hosted, so smbd
will not listen on any of the public IP addresses. When public IP addresses are eventually hosted, smbd
will not bind to the new addresses.
Using the Samba registry
A recommended way of ensuring that all Samba nodes have the same configuration is to put most configuration into the registry.
This means that smb.conf
can be as simple as:
[global] clustering = yes include = registry
The initial contents of the registry can then be placed into a file (say tmp.conf
):
[global] security = ADS logging = syslog log level = 1 netbios name = test workgroup = SAMBA realm = samba.example.com idmap config * : backend = autorid idmap config * : range = 1000000-1999999
and loaded from one of the nodes:
net conf import tmp.conf
Further net conf
commands such as net conf addshare
can then be used to continue configuration.
Configure CTDB to manage Samba
For CTDB to manage Samba, the 50.samba
event script must be enabled
ctdb event script enable legacy 50.samba
This causes CTDB to start and stop Samba at startup and shutdown. It also tells CTDB to monitor Samba.
Similarly, if using winbind
, CTDB should also be configured to manage it:
ctdb event script enable legacy 49.winbind
Please see the event
command in ctdb(1) for more details.
CTDB will manage and start/stop/restart the Samba services, so the operating system should be configured so these are not started/stopped automatically.
Red Hat Linux variants
If using a Red Hat Linux variant, the Samba services are smb
and winbind
. Starting them at boot time is not recommended and this can be disabled using chkconfig
.
chkconfig smb off chkconfig winbind off
The service names and mechanism for disabling them varies across operating systems.
Event scripts
CTDB clustering for Samba involves the 50.samba
and 49.winbind
event scripts. These are provided as part of CTDB and do not usually need to be changed.
There are several configuration variables that affect the operation of these scripts. Please see ctdb-script.options(5) for details.
Filesystem specific configuration
The cluster filesystem you use with ctdb plays a critical role in ensuring that CTDB works seamlessly. Here are some filesystem specific tips
If you are interested in testing a new cluster filesystem with CTDB then we strongly recommend looking at the page on testing filesystems using ping_pong to ensure that the cluster filesystem supports correct POSIX locking semantics.
IBM GPFS filesystem
The GPFS filesystem (now known as Spectrum Scale ) is a proprietary cluster filesystem that has been extensively tested with CTDB/Samba. When using GPFS, the following smb.conf settings are recommended
vfs objects = gpfs fileid gpfs:sharemodes = yes fileid:algorithm = fsname force unknown acl user = yes nfs4: mode = special nfs4: chown = yes nfs4: acedup = merge
The ACL related options should only be enabled if you have NFSv4 ACLs enabled on your filesystem
The most important of these options is the "fileid:algorithm". You risk data corruption if you use a different mapping backend with Samba and GPFS, because locking wilk break across nodes. NOTE: You must also load "fileid" as a vfs object in order for this to take effect.
A guide to configuring Samba with CTDB and GPFS can be found at Samba CTDB GPFS Cluster HowTo
RedHat GFS filesystem
Red Hat GFS is a native file system that interfaces directly with the Linux kernel file system interface (VFS layer).
The gfs_controld daemon manages mounting, unmounting, recovery and posix locks. Edit /etc/init.d/cman (If using RedHat Cluster Suite) to start gfs_controld with the '-l 0 -o 1' flags to optimize posix locking performance. You'll notice the difference this makes by running the ping_pong test with and without these options.
A complete HowTo document to setup clustered samba with CTDB and GFS2 is here: GFS CTDB HowTo
Lustre filesystem
Lustre® is a scalable, secure, robust, highly-available cluster file system. It is designed, developed and maintained by a number of companies ( Intel, Seagate ) and OpenSFS which is a not for profit organisation.
Tests have been done on Lustre releases of 1.4.x and 1.6.x with CTDB/Samba, The current lustre release is 2.5.2 . When mounting Lustre, an option of "-o flock" should be specified to enable cluster-wide byte range lock among all Lustre clients.
These two versions have differnt mechanisms of configuration and startup. More information is available at http://wiki.lustre.org.
In comparison of Lustre configurating, setting up CTDB/Samba on the two different versions keeps the same way. The following settings are recommended:
vfs objects = fileid fileid:algorithm = fsname
The options of "fileid:mapping" must be specified to avoid possibe data corruption.
GlusterFS filesystem
GlusterFS is a cluster file-system capable of scaling to several peta-bytes that is easy to configure. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. GlusterFS is based on a stackable user space design without compromising performance. It uses Linux File System in Userspace (FUSE) to achieve all this.
NOTE: GlusterFS has not yet had extensive testing but this is currently underway.
Currently from versions 2.0 to 2.0.4 of GlusterFS, it must be patched with:
http://patches.gluster.com/patch/813/
This is to ensure GlusterFS passes the ping_pong test. This issue is being tracked at:
http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=159
Update: As of GlusterFS 2.0.6 this has been fixed.
OCFS2
- OCFS2 - see http://oss.oracle.com/projects/ocfs2/
recommended settings:
vfs objects = fileid fileid:algorithm = fsid
OCFS2 1.4 offers cluster-wide byte-range locking.
Other cluster filesystems
If you can't find documentation about your choice of cluster filesystem and clustered Samba then you might need to work around some limitations.
Inconsistent device numbers
Locking will not work if a cluster filesystem does not provide uniform device numbers across nodes. It testing shows locking problems then you should test device number uniformity of your cluster filesystem.
To work around a lack of device number uniformity, the following settings should be used in the global section of the Samba configuration:
vfs objects = fileid fileid:algorithm = fsname
See vfs_fileid(8) for more information.
Testing clustered Samba
Once your cluster is up and running, you may wish to know how to test that it is functioning correctly. The following tests may help with that
Using smbcontrol
You can check for connectivity to the smbd daemons on each node using smbcontrol
- smbcontrol smbd ping
Using Samba4 smbtorture
The Samba4 version of smbtorture has several tests that can be used to benchmark a CIFS cluster. You can download Samba4 like this:
git clone git://git.samba.org/samba.git cd samba/source4
Then configure and compile it as usual. The particular tests that are helpful for cluster benchmarking are the RAW-BENCH-OPEN, RAW-BENCH-LOCK and BENCH-NBENCH tests. These tests take a unclist that allows you to spread the workload out over more than one node. For example:
smbtorture //localhost/data -Uuser%password RAW-BENCH-LOCK --unclist=unclist.txt --num-progs=32 -t60
The file unclist.txt should contain a list of share in your cluster (UNC format: //server//share). For example
//node1/data //node2/data //node3/data //node4/data
For NBENCH testing you need a client.txt file. A suitable file can be found in the dbench distribution at http://samba.org/ftp/tridge/dbench/