Openstack-ha Deployment Scenarios

Build OpenStack High Availability (Ha,high availability)

Clustering is not a high-reliability, commonly used to build high-reliability MySQL method has active-passive master Standby mode : Using DRBD to achieve the main standby disaster capacity, heartbeat or Corosync do heartbeat monitoring, service switching and even failover,pacemaker to switch and control services (resources), or similar mechanisms . The main use of pacemaker to achieve the MySQL active-passive high-availability set Group. One important technique is DRBD: (Distributed replication block device), or distributed replication block devices, which is often used in place of shared disks. it works by: on a host on the specified disk device write request, the data sent to a host of kernel, and then through a module in kernel, the same data to the B host of kernel, and then the B host to write its own designated disk device, Thus the synchronization of the two host data is realized, and the write operation is highly available. DRBD is generally a master one from, and all the read and write operations, Mount can only be performed on the primary node server, but between the master-slave DRBD server can be exchanged. herehave a Introduction to D-RBD . (http://lwn.net/Articles/329543/). This article describes the high reliability of OpenStack through pacemaker by using only shared disks and not using DRBD.

       novazookeeperheartbeatThis paper describes the use of zookeeper for heartbeat detection. MySQL HA with Pacemakerdescribes the use of pacemaker to provide highly reliable services, which is also a common solution. GaleraIt is an open source project for MYSQL/INNODB Synchronous multi-master cluster, which provides many advantages (such as synchronous replication, read and write to any node, automatic member control, automatic node join, small delay, etc.), can be referenced.

the working modes of pacemaker and DRBD and MySQL can be consulted as follows:

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Other programs, according to Mysqlperformance Blog, the availability of several high-availability solutions for MySQL can be as follows:

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3. Building high-availability OpenStack(high-availabilityOpenStack）

In general, high availability is the creation of redundant backups, common strategies are:

• Cluster working mode . Multi-machine interoperability, such that the mode is to backup each instance multiple copies, no central node, such as the distributed object Storage System Swift, nova-network multi-host mode .

• Autonomous mode . Sometimes, solving a single point of failure (SPoF) can simply use each node to work autonomously, through the master-slave relationship to reduce the failure of the main control node, such as NOVA-API only responsible for their own node.

• Primary and Standby mode . The common mode is active-passive cluster, active-passive, passive node in monitoring and backup mode, timely switch when failure, such as MySQL high-availability cluster, nova-use pacemaker and heartbeat to achieve.

• Dual Master mode . This mode of mutual assistance, RABBITMQ is the active-active cluster high availability, the nodes in the cluster can be replicated in the queue. Architecturally, so you don't have to worry that the passive node won't start or the delay is too big?

In summary, the deployment and application of OpenStack is constantly being tried and developed for OpenStack optimization and improvement. Need to practice tuning . Practice is very important, good design and ideas need to be proven in practice.

Each of the services of OpenStack is described above , and I am purely a catalyst. Hope to practice communication, but also hope that the time of the friends can be some of the deployment of some scenarios to add to onestack/hastack. For a discussion and description of OpenStack High Availability , you can take a look at the following areas:

http://docs.openstack.org/

http://wiki.openstack.org

novazookeeperheartbeat:http://wiki.openstack.org/novazookeeperheartbeat

This article is from the "OpenStack Private Cloud" blog, declined to reprint!

Openstack-ha Deployment Scenarios