Configuring clustered Samba: Difference between revisions

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= Goal =
= Setting up a simple CTDB Samba cluster =


Configure clustered Samba using a CTDB cluster
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.


= Note =
== Getting the code ==


This page still contains some details not directly relevant to clustering Samba. The documentation is being cleaned up and restructured.
You need two source trees, one is a copy of Samba3 with clustering patches, and the other is the ctdb code itself. Both source trees are stored in bzr repositories. See http://bazaar-vcs.org/ for more information on bzr.


= Prerequisites =
The fastest way to checkout an initial copy of the Samba3 tree with clustering patches is:
rsync -avz samba.org::ftp/unpacked/samba_3_0_ctdb .
To update this tree when improvements are made in the upstream code do this:
cd samba_3_0_ctdb
bzr merge http://samba.org/~tridge/samba_3_0_ctdb


* [[Basic CTDB configuration]]
To get an initial checkout of the ctdb code do this:
* [[Setting up a cluster filesystem]]
rsync -avz samba.org::ftp/unpacked/ctdb .
* [[Configuring the CTDB recovery lock]] (recommended)
To update this tree when improvements are made in the upstream code do this:
* [[Adding public IP addresses]] (or some other failover/load balancing scheme)
cd ctdb
bzr merge http://samba.org/~tridge/ctdb


=Samba Configuration=
== Building the Samba3 tree ==


Next you need to initialise the Samba password database, e.g.
To build a copy of Samba3 with clustering and ctdb support you should do this:
smbpasswd -a root
cd samba_3_0_ctdb/source
./autogen.sh
./configure --prefix=/gpfs0/samba/prefix --with-ctdb=/usr/src/ctdb --with-cluster-support --enable-pie=no
make proto
make


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.
You should replace the /gpfs0/samba/prefix path with the cluster shared storage path you will use to install Samba. The path should to be a directory that is the same on all nodes of the cluster. If you are setting up a virtual cluster on loopback then this can be any local directory.


==Critical smb.conf parameters==
The /usr/src/ctdb path should be replaced with the path to the ctdb sources that you downloaded above


A clustered Samba install must set some specific configuration parameters
== Building the CTDB tree ==


netbios name = something
To build a copy of the CTDB code you should do this:
clustering = yes
cd ctdb
idmap config * : backend = autorid
./autogen.sh
idmap config * : range = 1000000-1999999
./configure --prefix=/gpfs0/samba/prefix
make


NB:
== Installing Samba3 ==
* See [https://www.samba.org/samba/docs/man/manpages/idmap_autorid.8.html idmap(8)] for more information about the idmap configuration
* netbios name should be the same on all nodes


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.
To install Samba3 you should do this:


==Using the Samba registry==
cd samba_3_0_ctdb/source
make install


A recommended way of ensuring that all Samba nodes have the same configuration is to put most configuration into the registry.
If your path points to another version of Samba, it is recommended that you reset your path to point to the bin/ directory of this newer Samba installation (e.g. /gpfs0/samba/prefix/bin).
Then you need to configure an appropriate smb.conf. There is a very simple example in samba_3_0_ctdb/examples/ctdb. You need to put this smb.conf in the lib/ subdirectory of the prefix you chose above.


This means that <code>smb.conf</code> can be as simple as:
Next you need to initialise the Samba password database, e.g.

smbpasswd -a root
[global]
or if you have not reset your path to point to this newer version of Samba:
clustering = yes
/gpfs0/samba/prefix/bin/smbpasswd -a root
ctdb:registry.tdb = yes
include = registry

The initial contents of the registry can then be placed into a file (say <code>tmp.conf</code>):

[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 <code>net conf</code> commands such as <code>net conf addshare</code> can then be used to continue configuration.

= Configure CTDB to manage Samba =

For CTDB to manage Samba, the <code>50.samba</code> 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 <code>winbind</code>, CTDB should also be configured to manage it:

ctdb event script enable legacy 49.winbind

Please see the <code>event</code> command in [http://ctdb.samba.org/manpages/ctdb.1.html 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 <code>smb</code> and <code>winbind</code>. Starting them at boot time is not recommended and this can be disabled using <code>chkconfig</code>.

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 <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.

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.

= 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|ping_pong]] to ensure that the cluster filesystem supports correct POSIX locking semantics.

== IBM 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

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 ==

[http://www.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Global_File_System/index.html 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 [http://wiki.samba.org/index.php/Ping_pong 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 ( [http://www.intel.com/content/www/us/en/software/intel-solutions-for-lustre-software.html Intel], [http://www.seagate.com/products/enterprise-servers-storage/enterprise-storage-systems/clustered-file-systems/ Seagate] ) and [http://opensfs.org/ 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 ==

[http://www.gluster.org/ 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 [[Setting_up_a_cluster_filesystem#Checking_uniformity_of_device_and_inode_numbering|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 [https://www.samba.org/samba/docs/man/manpages/vfs_fileid.8.html vfs_fileid(8)] for more information.


= Testing clustered Samba =
Samba with clustering must use the tdbsam or ldap SAM passdb backends (it must not use the default smbpasswd backend). 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.


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
== Cluster Configuration ==


== Using smbcontrol ==
The main cluster configuration file is cluster_nodes.txt in your Samba configuration directory (the lib/ subdirectory of your Samba installation prefix). This file needs to be created and should contain a list of the IP addresses of your cluster nodes.


You can check for connectivity to the smbd daemons on each node using smbcontrol
== Starting the cluster ==


- smbcontrol smbd ping
There is an example startup script in samba_3_0_ctdb/examples/ctdb/cluster_start.sh.


== Loopback Setup ==
== 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:
For testing purposes you can setup a Samba/CTDB cluster on a single computer using loopback networking. To set this up you need to do this:


git clone git://git.samba.org/samba.git
- use ifconfig to create IP aliases for your loopback device for each virtual node
cd samba/source4
- put the list of aliases addresses in cluster_nodes.txt


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:
For example in order to create loopback devices 2 through 4 (lookpback device 1 already exists on most systems), you could do this:


smbtorture //localhost/data -Uuser%password RAW-BENCH-LOCK --unclist=unclist.txt --num-progs=32 -t60
for i in `seq 2 4`; do
ifconfig lo:$i 127.0.0.$i
done


The file unclist.txt should contain a list of share in your cluster (UNC format: ''//server//share''). For example
then to configure these you would create a cluster_nodes.txt with the lines:


//node1/data
127.0.0.1
//node2/data
127.0.0.2
//node3/data
127.0.0.3
//node4/data
127.0.0.4


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/
Then start the cluster as above. For the system to start you also need an onnode script in your path. The onnode.loop example script can be used to create onnode. The user rarely needs to directly invoke this script but it is used by the cluster startup script to remotely execute commands on other cluster nodes. The last line of onnode.ssh, which contains the sample command for starting ssh may have to be changed (e.g. for certain Kerberized ssh configurations) when the cluster is run over multiple nodes.

Revision as of 07:38, 29 September 2020

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

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
       ctdb:registry.tdb = 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

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/