Difference between pages "OpenStack Architecture" and "Repository Configuration"

From Funtoo
(Difference between pages)
Jump to navigation Jump to search
 
(Undo revision 9202 by Duncan.britton (talk))
 
Line 1: Line 1:
This page exists to document [http://www.openstack.org OpenStack] configuration.
{{Warning|This article is a work-in-progress referring to a future Portage version. It does not apply to the current Funtoo Portage version. Please do not update your configuration yet.}}


Note that the current approach is to use devstack, which is not a good way to learn OpenStack. So much of this document will be about doing a devstack-like configuration for Funtoo.
Starting with Portage-2.3.8, a switch to a new repository configuration framework is complete and users may want to update their configuration files. This document aims to describe the goals for the new framework and how to use it.


This document will split OpenStack configuration into each architectural component, describing configuration steps for each component separately.
== Multiple repository layout ==
One of the most important changes is the switch from the old ''overlay'' layout to a new cleaner ''repository'' system. The new layout is more flexible and more predictable. For example, repositories can now use resources (eclasses, for example) provided by other repositories.


== SQL Database ==
The old layout was based on the concept of one ''main tree'' and optionally a number of overlays. The main tree provided base system ebuilds, eclasses, profiles, while overlays mostly were able to provide their own ebuilds. The ebuild provided by overlays overrode the ebuilds in main tree to the extend of making it impossible to install the main tree version. Overlays could also provide eclasses for their own ebuilds and package.* entries that applied to all overlays and to the main tree. The Package Manager is responsible for updating the main tree, while overlays are managed externally.


A number of OpenStack services use a SQL back-end for storing various bits of data.
The new layout is based on the concept of one or more configurable repositories. Each repository can either be stand-alone or depend upon other repositories. The distribution provides a repository called ''funtoo'' (a drop-in replacement for Gentoo's ''gentoo'' repository). Users can install more repositories at they will, the repositories providing their own ebuilds, eclasses and profiles as necessary and/or using them from other repositories. Users can explicitly choose the repository they want to install packages from. The Package Manager can update all repositories.


While DevStack uses MySQL for its SQL deployment, multiple database back-ends are actually supported thanks to [http://sqlalchemy.org SQLAlchemy] being used behind the scenes, which is a re-targetable Python database API. Thus, it should be possible to use Postgres, etc, by simply using different connection strings. A list of SQLAlchemy connection types can be found on [http://docs.sqlalchemy.org/en/latest/core/engines.html this SQLAlchemy documentation page.]
== Portage configuration ==
=== New repository layout ===
The repository configuration should be stored in <code>/etc/portage/repos.conf</code>. It can be either a single file or a directory containing one or more ''.conf'' files.


Using a single root database user account for all services is not a good policy for production deployment. Ideally, each service should have its own restricted user account with only the ability to access its own database.
The default configuration is installed as <code>/usr/share/portage/config/repos.conf</code>. This file is internal configuration file installed with portage ebuild and should '''not''' be modified. Instead, the configuration in <code>/etc/portage/repos.conf</code> can override the defaults specified there.


Let's look at how each service is configured in regards to SQL:
The configuration uses format similar to Windows .ini files. Each section heading (repository name in square brackets) signifies a single repository, followed by one or more key-value option pairs. For example, the following file copies default configuration for Funtoo repository:


=== nova ===  
{{file|name=/etc/portage/repos.conf/funtoo.conf|desc=Example configuration override for Funtoo repository to move it to non-standard location|body=
[funtoo]
# moved to non-standard location!
location = /var/db/repos/funtoo
sync-type = git
sync-uri = git://github.com/funtoo/ports-2015.git
auto-sync = yes
}}


Here's how to set up a MySQL database back-end for nova and tell nova to initialize its database tables:
The most useful repository configuration options are listed below:
;location: ''Obligatory.'' Specifies the directory where repository is/will be stored. If Portage knows how to sync the repository and the location does not exist, it will be created on next ''emerge --sync''. Otherwise, the directory must exist.
;priority: Specifies the priority used for ordering ebuilds from different repositories. If two repositories provide an ebuild with matching versions, the repository with higher priority will be used.
;auto-sync: Specifies whether ''emerge --sync'' should update the repository. Defaults to ''yes'' if ''sync-type'' is specified, ''no'' otherwise.
;sync-depth: Specifies ''--depth'' for git clone. Used only on initial sync. Defaults to 1. Can be set to 0 to force full clone (not pass ''--depth'' at all).
;sync-type: Specifies syncing/update method. Can be one of: ''cvs'', ''git'', ''rsync'', ''svn''.
;sync-umask: Specifies the umask used when updating/syncing the repository.
;sync-uri: Specifies remote URI from which the repository will be cloned/synced. Can use any syntax valid for a particular syncing method.
;sync-user: Specifies the user[:group] used to update/sync the repository. If ''FEATURES=usersync'' is used, defaults to the credentials of directory owner.


<console>
Additionally a <code>[DEFAULT]</code> section may be specified. Options in this section are used as defaults for all repositories.
mysql> ##i##create database nova character set latin1;
Query OK, 1 row affected (0.02 sec)


mysql> ##i##grant all privileges on nova.* to nova@localhost identified by 'foobar';
=== Migrating existing configurations ===
Query OK, 0 rows affected (0.00 sec)
The new configuration format provides replacement for existing configuration done through <code>/etc/portage/make.conf</code> and environment variables. While the variables are still supported for backwards compatibility, users are recommended to move to the new configuration scheme. Funtoo portage ebuild is planned to  make the migration unattended (repos.conf installed automatically to ease the config steps) with the following file:
</console>
{{file|name=/etc/portage/repos.conf/funtoo.conf|body=
[funtoo]
location = /usr/portage
sync-type = git
sync-uri = git://github.com/funtoo/ports-2015.git
auto-sync = yes
}}
The following replacements are provided for existing variables:
;PORTDIR: Used to specify main tree location. Replaced by ''location'' key in the section corresponding to the default repository (<code>[funtoo]</code> by default).
;PORTDIR_OVERLAY: Used to specify locations of overlays. Each of the paths needs to be replaced with a separate repository section, with the path placed in ''location'' key. Additionally, ''priority'' may be used to force specific ordering of ebuild overrides.
;SYNC: Used to specify URI for syncing the main repository, also implied a protocol for doing that. Replaced by the ''sync-uri'' and ''sync-type'' keys in the default repository section.
;SYNC_UMASK: Used to specify umask for syncing repositories. Replaced by ''sync-umask'' key in repository configuration. Can be specified in <code>[DEFAULT]</code> section to apply to all repositories.
;SYNC_USER: Used to specify user credentials for syncing repositories. Replaced by ''sync-user'' key in repository configuration. Can be specified in <code>[DEFAULT]</code> section to apply to all repositories.


Now set the following connection string in <tt>/etc/nova/nova.conf</tt>:
{{file|name=/etc/portage/make.conf|desc=Example old make.conf file|body=
# user changed PORTDIR location
PORTDIR="/var/db/repos/funtoo"
PORTDIR_OVERLAY="/var/db/repos/foo /var/db/repos/bar"


<pre>
SYNC="git://github.com/funtoo/ports-2015.git"
--sql_connection=mysql://nova:foobar@localhost/nova
SYNC_USER="oleg"
</pre>
SYNC_UMASK="022"
}}


Note the use of the latin1 character set when we created the tables in MySQL. This is so the following command will not cause an error due to the default UTF-8 character set creating indexes that are too big for MySQL to handle:
{{file|name=/etc/portage/repos.conf|desc=Replacement repos.conf file|body=
[DEFAULT]
sync-user = oleg
sync-umask = 022


<console>
[funtoo]
# ##i##nova-manage db sync
location = /var/db/repos/funtoo
2012-03-02 21:31:14 DEBUG nova.utils [-] backend <module 'nova.db.sqlalchemy.migration' from '/usr/lib64/python2.7/site-packages/nova/db/sqlalchemy/migration.pyc'> from (pid=17779) __get_b
sync-type = git
ackend /usr/lib64/python2.7/site-packages/nova/utils.py:602
sync-uri = git://github.com/funtoo/ports-2015.git
</console>


After running the command above, you should now have all the relevant database tables created:
[foo]
location = /var/db/repos/foo
priority = 1


<console>
[bar]
xdev var # ##i##mysql -u root -p nova
location = /var/db/repos/bar
Enter password:
priority = 2
Reading table information for completion of table and column names
}}
You can turn off this feature to get a quicker startup with -A


Welcome to the MySQL monitor. Commands end with ; or \g.
The <code>repos.conf</code> configuration can be further extended with ''sync-type'' and ''sync-uri'' for overlays to get ''emerge --sync'' updating them automatically.
Your MySQL connection id is 16
Server version: 5.1.61-log Gentoo Linux mysql-5.1.61


Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
let's see a real example of tree and overlays added.
{{file|name=/etc/portage/repos.conf|desc=Replacement repos.conf file|body=


Oracle is a registered trademark of Oracle Corporation and/or its
[gentoo]
affiliates. Other names may be trademarks of their respective
location = /usr/portage
owners.
sync-type = git
 
sync-uri = git://github.com/funtoo/ports-2012.git
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
 
[funtoo-overlay]
mysql> ##i##show tables;
location = /root/git/funtoo-overlay
+-------------------------------------+
| Tables_in_nova                      |
[funtoo-gnome]
+-------------------------------------+
location = /root/git/funtoo-gnome-overlay
| agent_builds                        |
}}
| aggregate_hosts                    |
funtoo-overlay and funtoo-gnome-overlay are an overlays added on top of regular portage tree.
| aggregate_metadata                  |
[[Category:Portage]]
| aggregates                          |
| auth_tokens                        |
| block_device_mapping                |
| bw_usage_cache                      |
| certificates                        |
| compute_nodes                      |
| console_pools                      |
...
</console>
 
You have now validated that nova is connecting to your MySQL database correctly.
 
=== glance ===
 
From glance.openstack.org:
 
<blockquote>The Glance project provides services for discovering, registering, and retrieving virtual machine images. Glance has a RESTful API that allows querying of VM image metadata as well as retrieval of the actual image.</blockquote>
 
Glance typically uses a MySQL database called <tt>glance</tt>, although the name is configurable in the connection string.
 
SQL connection settings might be stored in a glance configuration file located at <tt>/opt/stack/glance/etc/glance-registry.conf</tt>. In the devstack installation process, <tt>/opt/stack/glance</tt> contains a git checkout of the glance software.
 
The SQL connection configuration string might look something like this:
 
<pre>
sql_connection = mysql://glance:yourpassword@192.168.206.130/glance
</pre>
 
More info on glance configuration is available [http://docs.openstack.org/diablo/openstack-compute/install/content/glance-registry-conf-file.html here].
 
=== keystone ===
 
Keystone, the OpenStack identity service, also uses SQL. <tt>etc/keystone.conf</tt> keystone install/git repo directory is used to store the SQL configuration:
 
<pre>
sql_connection = %SQL_CONN%
</pre>
 
As everything else, the SQL connection string uses SQLAlchemy syntax.
 
=== Quantum and Open VSwitch ===
 
<blockquote>Quantum is an incubated OpenStack project to provide "network connectivity as a service" between interface devices (e.g., vNICs) managed by other Openstack services (e.g., nova).</blockquote>
 
[http://openvswitch.org Open VSwitch] is described as:
 
<blockquote>Open vSwitch is a production quality, multilayer virtual switch licensed under the open source Apache 2.0 license. It is designed to enable massive network automation through programmatic extension, while still supporting standard management interfaces and protocols (e.g. NetFlow, sFlow, SPAN, RSPAN, CLI, LACP, 802.1ag). In addition, it is designed to support distribution across multiple physical servers similar to VMware's vNetwork distributed vswitch or Cisco's Nexus 1000V. </blockquote>
 
There is an [http://openvswitch.org/openstack/documentation/ Open VSwitch Plug-in for OpenStack Quantum] which can be set up by DevStack. This plug-in uses SQL storage. The SQLAlchemy connection string is stored in (relative to git/install root) <tt>etc/quantum/plugins/openvswitch/ovs_quantum_plugin.ini</tt>. Similarly to everything but nova, the SQL connection string is stored in <tt>sql_connection =</tt> format.
 
If the plugin is enabled, the following settings are added to nova.conf:
 
<pre>
--libvirt_vif_type=ethernet
--libvirt_vif_driver=nova.virt.libvirt.vif.LibvirtOpenVswitchDriver
--linuxnet_interface_driver=nova.network.linux_net.LinuxOVSInterfaceDriver
--quantum_use_dhcp
</pre>
 
=== Melange ===
 
From the Melange site:
 
<blockquote>
Melange is intended to provide network information services for use across OpenStack services. The initial focus will be on IP address management (IPAM) and address discovery (DHCP/dnsmasq) functionality. Melange is intended to be a standalone service with it's own API. However, the initial use case will be to decouple existing IP management and VM address discovery from Nova and support the existing Nova networking capabilities.
</blockquote>
 
Melange also uses a <tt>sql_connection =</tt> string stored in its <tt>etc/melange/melange.conf</tt> (relative to install/git root).
 
== RabbitMQ ==
 
RabbitMQ  is a reliable messaging framework used by OpenStack. Currently, it looks like only nova uses it. Nova is configured to connect to rabbitmq by setting the following lines in <tt>/etc/nova/nova.conf</tt>:
 
<pre>
--rabbit_host=$RABBIT_HOST
--rabbit_password=$RABBIT_PASSWORD
</pre>
 
Rabbit's password is configured using the following command, as root:
 
<console>
# ##i##rabbitmqctl change_password guest $RABBIT_PASSWORD
</console>
 
I am not yet completely sure how RabbitMQ fits into the OpenStack architecture. It may be that the supporting services expect it to be running locally, and that Nova compute nodes need to hook into a Nova instance, which would typically be running remotely. (Thus the ability for DevStack to target a remote RabbitMQ host.)
 
== Virtualization Technology ==
 
DevStack defaults to configuring OpenStack to use libvirt with [[KVM]], and will fall back to basic [[QEMU]] support if the <tt>kvm</tt> kernel module is not available. It also has support for using libvirt with [[LXC]], in addition to using [[Xen]] Server directly (bypassing libvirt.)
 
 
[[Category:Virtualization]]
[[Category:OpenStack]]

Revision as of 04:52, February 27, 2015

   Warning

This article is a work-in-progress referring to a future Portage version. It does not apply to the current Funtoo Portage version. Please do not update your configuration yet.

Starting with Portage-2.3.8, a switch to a new repository configuration framework is complete and users may want to update their configuration files. This document aims to describe the goals for the new framework and how to use it.

Multiple repository layout

One of the most important changes is the switch from the old overlay layout to a new cleaner repository system. The new layout is more flexible and more predictable. For example, repositories can now use resources (eclasses, for example) provided by other repositories.

The old layout was based on the concept of one main tree and optionally a number of overlays. The main tree provided base system ebuilds, eclasses, profiles, while overlays mostly were able to provide their own ebuilds. The ebuild provided by overlays overrode the ebuilds in main tree to the extend of making it impossible to install the main tree version. Overlays could also provide eclasses for their own ebuilds and package.* entries that applied to all overlays and to the main tree. The Package Manager is responsible for updating the main tree, while overlays are managed externally.

The new layout is based on the concept of one or more configurable repositories. Each repository can either be stand-alone or depend upon other repositories. The distribution provides a repository called funtoo (a drop-in replacement for Gentoo's gentoo repository). Users can install more repositories at they will, the repositories providing their own ebuilds, eclasses and profiles as necessary and/or using them from other repositories. Users can explicitly choose the repository they want to install packages from. The Package Manager can update all repositories.

Portage configuration

New repository layout

The repository configuration should be stored in /etc/portage/repos.conf. It can be either a single file or a directory containing one or more .conf files.

The default configuration is installed as /usr/share/portage/config/repos.conf. This file is internal configuration file installed with portage ebuild and should not be modified. Instead, the configuration in /etc/portage/repos.conf can override the defaults specified there.

The configuration uses format similar to Windows .ini files. Each section heading (repository name in square brackets) signifies a single repository, followed by one or more key-value option pairs. For example, the following file copies default configuration for Funtoo repository:

   /etc/portage/repos.conf/funtoo.conf - Example configuration override for Funtoo repository to move it to non-standard location
[funtoo]
# moved to non-standard location!
location = /var/db/repos/funtoo
sync-type = git
sync-uri = git://github.com/funtoo/ports-2015.git
auto-sync = yes

The most useful repository configuration options are listed below:

location
Obligatory. Specifies the directory where repository is/will be stored. If Portage knows how to sync the repository and the location does not exist, it will be created on next emerge --sync. Otherwise, the directory must exist.
priority
Specifies the priority used for ordering ebuilds from different repositories. If two repositories provide an ebuild with matching versions, the repository with higher priority will be used.
auto-sync
Specifies whether emerge --sync should update the repository. Defaults to yes if sync-type is specified, no otherwise.
sync-depth
Specifies --depth for git clone. Used only on initial sync. Defaults to 1. Can be set to 0 to force full clone (not pass --depth at all).
sync-type
Specifies syncing/update method. Can be one of: cvs, git, rsync, svn.
sync-umask
Specifies the umask used when updating/syncing the repository.
sync-uri
Specifies remote URI from which the repository will be cloned/synced. Can use any syntax valid for a particular syncing method.
sync-user
Specifies the user[:group] used to update/sync the repository. If FEATURES=usersync is used, defaults to the credentials of directory owner.

Additionally a [DEFAULT] section may be specified. Options in this section are used as defaults for all repositories.

Migrating existing configurations

The new configuration format provides replacement for existing configuration done through /etc/portage/make.conf and environment variables. While the variables are still supported for backwards compatibility, users are recommended to move to the new configuration scheme. Funtoo portage ebuild is planned to make the migration unattended (repos.conf installed automatically to ease the config steps) with the following file:

   /etc/portage/repos.conf/funtoo.conf 
[funtoo]
location = /usr/portage
sync-type = git
sync-uri = git://github.com/funtoo/ports-2015.git
auto-sync = yes

The following replacements are provided for existing variables:

PORTDIR
Used to specify main tree location. Replaced by location key in the section corresponding to the default repository ([funtoo] by default).
PORTDIR_OVERLAY
Used to specify locations of overlays. Each of the paths needs to be replaced with a separate repository section, with the path placed in location key. Additionally, priority may be used to force specific ordering of ebuild overrides.
SYNC
Used to specify URI for syncing the main repository, also implied a protocol for doing that. Replaced by the sync-uri and sync-type keys in the default repository section.
SYNC_UMASK
Used to specify umask for syncing repositories. Replaced by sync-umask key in repository configuration. Can be specified in [DEFAULT] section to apply to all repositories.
SYNC_USER
Used to specify user credentials for syncing repositories. Replaced by sync-user key in repository configuration. Can be specified in [DEFAULT] section to apply to all repositories.
   /etc/portage/make.conf - Example old make.conf file
# user changed PORTDIR location
PORTDIR="/var/db/repos/funtoo"
PORTDIR_OVERLAY="/var/db/repos/foo /var/db/repos/bar"

SYNC="git://github.com/funtoo/ports-2015.git"
SYNC_USER="oleg"
SYNC_UMASK="022"
   /etc/portage/repos.conf - Replacement repos.conf file
[DEFAULT]
sync-user = oleg
sync-umask = 022

[funtoo]
location = /var/db/repos/funtoo
sync-type = git
sync-uri = git://github.com/funtoo/ports-2015.git

[foo]
location = /var/db/repos/foo
priority = 1

[bar]
location = /var/db/repos/bar
priority = 2

The repos.conf configuration can be further extended with sync-type and sync-uri for overlays to get emerge --sync updating them automatically.

let's see a real example of tree and overlays added.

   /etc/portage/repos.conf - Replacement repos.conf file
[gentoo]
location = /usr/portage
sync-type = git
sync-uri = git://github.com/funtoo/ports-2012.git
 
[funtoo-overlay]
location = /root/git/funtoo-overlay
 
[funtoo-gnome]
location = /root/git/funtoo-gnome-overlay

funtoo-overlay and funtoo-gnome-overlay are an overlays added on top of regular portage tree.

Retrieved from "https://www.funtoo.org/index.php?title=OpenStack_Architecture&oldid=9204"