Add AFS docs
Change-Id: I11a5e13a9aca71ea1368b6e9df61a606ea3746c3
This commit is contained in:
James E. Blair
Jeremy Stanley
parent
b4b5724a0b
commit
3f2923671c
|
|
@ -0,0 +1,192 @@
|
|||
:title: OpenAFS
|
||||
|
||||
.. _openafs:
|
||||
|
||||
OpenAFS
|
||||
#######
|
||||
|
||||
The Andrew Filesystem (or AFS) is a global distributed filesystem.
|
||||
With a single mountpoint, clients can access any site on the Internet
|
||||
which is running AFS as if it were a local filesystem.
|
||||
|
||||
OpenAFS is an open source implementation of the AFS services and
|
||||
utilities.
|
||||
|
||||
A collection of AFS servers and volumes that are collectively
|
||||
administered within a site is called a ``cell``. The OpenStack
|
||||
project runs the ``openstack.org`` AFS cell, accessible at
|
||||
``/afs/openstack.org/``.
|
||||
|
||||
At a Glance
|
||||
===========
|
||||
|
||||
:Hosts:
|
||||
* afsdb01.openstack.org (a vldb and pts server in DFW)
|
||||
* afsdb02.openstack.org (a vldb and pts server in ORD)
|
||||
* afs01.dfw.openstack.org (a fileserver in DFW)
|
||||
* afs01.ord.openstack.org (a fileserver in ORD)
|
||||
:Puppet:
|
||||
* :file:`modules/openafs`
|
||||
* :file:`modules/openstack_project/manifests/afsdb.pp`
|
||||
* :file:`modules/openstack_project/manifests/afsfs.pp`
|
||||
:Projects:
|
||||
* http://openafs.org/
|
||||
:Bugs:
|
||||
* http://bugs.launchpad.net/openstack-ci
|
||||
* http://rt.central.org/rt/Search/Results.html?Order=ASC&DefaultQueue=10&Query=Queue%20%3D%20%27openafs-bugs%27%20AND%20%28Status%20%3D%20%27open%27%20OR%20Status%20%3D%20%27new%27%29&Rows=50&OrderBy=id&Page=1&Format=&user=guest&pass=guest
|
||||
:Resources:
|
||||
* `OpenAFS Documentation <http://docs.openafs.org/index.html>`_
|
||||
|
||||
OpenStack Cell
|
||||
--------------
|
||||
|
||||
AFS may be one of the most thoroughly documented systems in the world.
|
||||
There is plenty of very good information about how AFS works and the
|
||||
commands to use it. This document will only cover the mininmum needed
|
||||
to understand our deployment of it.
|
||||
|
||||
OpenStack runs an AFS cell called ``openstack.org``. There are three
|
||||
important services provided by a cell: the volume location database
|
||||
(VLDB), the protection database (PTS), and the file server (FS). The
|
||||
volume location service answers queries from clients about which
|
||||
fileservers should be contacted to access particular volumes, while
|
||||
the protection service provides information about users and groups.
|
||||
|
||||
Our implementation follows the common recommendation to colocate the
|
||||
VLDB and PTS servers, and so they both run on our afsdb* servers.
|
||||
These servers all have the same information and communicate with each
|
||||
other to keep in sync and automatically provide high-availability
|
||||
service. For that reason, one of our DB servers is in the DFW region,
|
||||
and the other in ORD.
|
||||
|
||||
Fileservers contain volumes, each of which is a portion of the file
|
||||
space provided by that cell. A volume appears as at least one
|
||||
directory, but may contain directories within the volume. Volumes are
|
||||
mounted within other volumes to construct the filesystem hierarchy of
|
||||
the cell.
|
||||
|
||||
OpenStack has one fileserver in DFW and one in ORD. They do not
|
||||
automatically contain copies of the same data. A read-write volume in
|
||||
AFS can only exist on exactly one fileserver, and if that fileserver
|
||||
is out of service, the volumes it serves are not available. However,
|
||||
volumes may have read-write copies which are stored on other
|
||||
fileservers. If a client requests a read-only volume, as long as one
|
||||
site with a read-only volume is online, it will be available.
|
||||
|
||||
Client Configuration
|
||||
--------------------
|
||||
|
||||
To use OpenAFS on a Debian or Ubuntu machine::
|
||||
|
||||
sudo apt-get install openafs-client openafs-krb5 krb5-user
|
||||
|
||||
Debconf will ask you for a default realm, cell and cache size.
|
||||
Answer::
|
||||
|
||||
Default Kerberos version 5 realm: OPENSTACK.ORG
|
||||
AFS cell this workstation belongs to: openstack.org
|
||||
Size of AFS cache in kB: 500000
|
||||
|
||||
The default cache size in debconf is 50000 (50MB) which is not very
|
||||
large. We recommend setting it to 500000 (500MB -- add a zero to the
|
||||
default debconf value), or whatever is appropriate for your system.
|
||||
|
||||
The OpenAFS client is not started by default, so you will need to
|
||||
run::
|
||||
|
||||
sudo service openafs-client start
|
||||
|
||||
When it's done, you should be able to ``cd /afs/openstack.org``.
|
||||
|
||||
Most of what is in our AFS cell does not require authentication.
|
||||
However, if you have a principal in kerberos, you can get an
|
||||
authentication token for use with AFS with::
|
||||
|
||||
kinit
|
||||
aklog
|
||||
|
||||
Administration
|
||||
--------------
|
||||
|
||||
The following information is relevant to AFS administrators.
|
||||
|
||||
All of these commands have excellent manpages which can be accessed
|
||||
with commands like ``man vos`` or ``man vos create``. They also
|
||||
provide short help messages when run like ``vos -help`` or ``vos
|
||||
create -help``.
|
||||
|
||||
For all administrative commands, you may either run them from any AFS
|
||||
client machine while authenticated as an AFS admin, or locally without
|
||||
authentication on an AFS server machine by appending the `-localauth`
|
||||
flag to the end of the command.
|
||||
|
||||
Adding a User
|
||||
~~~~~~~~~~~~~
|
||||
First, add a kerberos principal as described in :ref:`addprinc`. Have the
|
||||
username and UID from puppet ready.
|
||||
|
||||
Then add the user to the protection database with::
|
||||
|
||||
pts createuser $USERNAME -id UID
|
||||
|
||||
Admin UIDs start at 1 and increment. If you are adding a new admin
|
||||
user, you must run ``pts listentries``, find the highest UID for an
|
||||
admin user, increment it by one and use that as the UID. The username
|
||||
for an admin user should be in the form ``username.admin``.
|
||||
|
||||
.. note::
|
||||
Any '/' characters in a kerberos principal become '.' characters in
|
||||
AFS.
|
||||
|
||||
Adding a Superuser
|
||||
~~~~~~~~~~~~~~~~~~
|
||||
Run the following commands to add an existing principal to AFS as a
|
||||
superuser::
|
||||
|
||||
bos adduser -server afsdb01.openstack.org -user $USERNAME.admin
|
||||
bos adduser -server afsdb02.openstack.org -user $USERNAME.admin
|
||||
pts adduser -user $USERNAME.admin -group system:administrators
|
||||
|
||||
Creating a Volume
|
||||
~~~~~~~~~~~~~~~~~
|
||||
|
||||
Select a fileserver for the read-write copy of the volume according to
|
||||
which region you wish to locate it after ensuring it has sufficient
|
||||
free space. Then run::
|
||||
|
||||
vos create $FILESERVER a $VOLUMENAME
|
||||
|
||||
The `a` in the preceding command tells it to place the volume on
|
||||
partition `vicepa`. Our fileservers only have one partition and therefore
|
||||
this is a constant.
|
||||
|
||||
Be sure to mount the volume in AFS with::
|
||||
|
||||
fs mkmount /afs/openstack.org/path/to/mountpoint $VOLUMENAME
|
||||
|
||||
You may want to create read-only sites for the volume with ``vos
|
||||
addsite`` and then ``vos release``.
|
||||
|
||||
You should set the volume quota with ``fs setquota``.
|
||||
|
||||
Adding a Fileserver
|
||||
~~~~~~~~~~~~~~~~~~~
|
||||
Put the machine's public IP on a single line in
|
||||
/var/lib/openafs/local/NetInfo (TODO: puppet this).
|
||||
|
||||
Copy ``/etc/openafs/server/KeyFile`` from an existing fileserver.
|
||||
|
||||
Create an LVM volume named ``vicepa`` from cinder volumes. See
|
||||
:ref:`cinder` for details on volume management. Then run::
|
||||
|
||||
mkdir /vicepa
|
||||
echo "/dev/main/vicepa /vicepa ext4 errors=remount-ro,barrier=0 0 2" >>/etc/fstab
|
||||
mount -a
|
||||
|
||||
Finally, create the fileserver with::
|
||||
|
||||
bos create NEWSERVER dafs dafs \
|
||||
-cmd "/usr/lib/openafs/dafileserver -p 23 -busyat 600 -rxpck 400 -s 1200 -l 1200 -cb 65535 -b 240 -vc 1200" \
|
||||
-cmd /usr/lib/openafs/davolserver \
|
||||
-cmd /usr/lib/openafs/salvageserver \
|
||||
-cmd /usr/lib/openafs/dasalvager
|
||||
|
|
@ -54,10 +54,23 @@ Copy the file `/etc/krb5.keytab` to the second kdc host.
|
|||
|
||||
The puppet config sets up slave propogation scripts and cron jobs to run them.
|
||||
|
||||
.. _addprinc:
|
||||
|
||||
Adding principals
|
||||
-----------------
|
||||
|
||||
To add an admin principal::
|
||||
First, ensure the user has an entry in puppet so they have a unix
|
||||
shell account on our hosts. SSH access is not necessary, but keeping
|
||||
track of usernames and uids with account entries is necessary.
|
||||
|
||||
# execute kadmin.local then run these commands
|
||||
addprinc corvus/admin@OPENSTACK.ORG
|
||||
Then, add the user to Kerberos using kadmin (while authenticated as a
|
||||
kerberos admin) or kadmin.local on the kdc::
|
||||
|
||||
kadmin: addprinc $USERNAME@OPENSTACK.ORG
|
||||
|
||||
Where `$USERNAME` is the lower-case username of their unix account in
|
||||
puppet. `OPENSTACK.ORG` should be capitalized.
|
||||
|
||||
If you are adding an admin principal, use
|
||||
`username/admin@OPENSTACK.ORG`. Admins should additionally have
|
||||
regular user principals.
|
||||
|
|
|
|||
|
|
@ -29,6 +29,7 @@ Major Systems
|
|||
openstackid
|
||||
storyboard
|
||||
kerberos
|
||||
afs
|
||||
|
||||
.. NOTE(dhellmann): These projects were not listed above, or in any
|
||||
other toctree, which breaks the build. It's not clear why they were
|
||||
|
|
|
|||
Loading…
Reference in New Issue