The RHCS testing process (including GFS2) is not complete!

RHCS Testing Process

1. RHCS component Introduction

(1) distributed Cluster Manager CMAN)

Cluster Manager (CMAN) is a distributed Cluster management tool that runs on each node of the Cluster and provides Cluster management tasks for RHCS.

CMAN is used to manage cluster members, messages, and notifications. It monitors the running status of each node to understand the relationship between node members. When a node in the cluster fails, the node member relationship will change, and CMAN promptly notifies the underlying layer of this change, and then make corresponding adjustments.

(2) Lock Management DLM)

Distributed LockManager (DLM) is a Distributed lock manager. It is an underlying component of RHCS and provides a common lock operation mechanism for the cluster. In the RHCS cluster system, DLM runs on each node in the cluster. GFS uses the lock mechanism of the lock manager to synchronize access to the file system metadata. CLVM synchronously updates data to LVM volumes and volume groups through the lock manager.

DLM does not need to set the lock management server. It adopts the peering lock management method, which greatly improves the processing performance. At the same time, DLM avoids the performance bottleneck of overall recovery when a single node fails. In addition, DLM requests are local and do not require network requests, so the requests take effect immediately. Finally, the DLM uses a layered mechanism to implement parallel lock modes for multiple lock spaces.

(3) configuration file management (CCS)

Cluster ConfigurationSystem (CCS) is mainly used for managing Cluster configuration files and synchronizing configuration files between nodes. CCS runs on each node of the cluster and monitors a single configuration file/etc/cluster on each cluster node. conf status. When this file changes, it is updated to every node in the cluster, and the configuration file of each node is synchronized at all times. For example, the administrator updates the cluster configuration file on node A. After CCS finds that the configuration file of node A has changed, the change will be immediately transmitted to other nodes.

The rhcs configuration file is cluster. conf, which is an xml file containing the cluster name, cluster node information, cluster resources and service information, and fence devices.

(4) gate device FENCE)

FENCE devices are an essential part of the RHCS cluster. FENCE devices can be used to avoid split-brain problems caused by unpredictable situations and FENCE devices, to solve these problems, Fence devices directly issue hardware management commands to servers or storage through the hardware management interfaces of servers or storage, or external power management devices, restart or shut down the server, or disconnect from the network.

FENCE works in the following way: when a host is abnormal or down due to an accident, the Standby opportunity first calls the FENCE device, and then restarts or isolates the abnormal host from the network through the FENCE device, after the FENCE operation is successfully executed, the information is returned to the slave machine. After receiving the successful information of FENCE, the slave machine starts to take over the services and resources of the host. In this way, resources occupied by abnormal nodes are released through the FENCE device, ensuring that resources and services always run on one node.

Rhcs fence devices can be divided into two types: Internal FENCE and external FENCE. Common internal FENCE devices include ibm rsaii cards, HP iLO cards, and IPMI devices, external fence devices include UPS, san switch, and network switch.

Middleware, high-availability Service Manager rgmanager)

High Availability service management is mainly used to supervise, start, and stop cluster applications, services, and resources. It provides a management capability for cluster services. When a node fails, the high availability cluster service management process can transfer services from this failed node to other healthy nodes, in addition, this service transfer capability is automatic and transparent.

RHCS uses rgmanager to manage cluster services. rgmanager runs on each cluster node and the corresponding process on the server is clurgmgrd.

In a RHCS cluster, high availability services include cluster services and cluster resources. Cluster services are actually application services, such as apache and mysql. There are many cluster resources, for example, an IP address, a running script, and an ext3/GFS file system.

In a RHCS cluster, the high availability service is combined with a Failover domain. A failover domain is a collection of cluster nodes that run specific services. In the failed transfer domain, you can set a priority for each node. The priority is used to determine the order of service transfer when the node fails. If no priority is specified for the node, the Cluster High Availability service will be transferred between any nodes. Therefore, by creating a failed transfer domain, you can not only set the order of service transfer between nodes, but also restrict a service to switch only within the node specified by the failed transfer domain.

Callback, Redhat GFS

GFS is a storage solution provided by RHCS for cluster systems. It allows multiple nodes in the cluster to share storage at the block level. Each node shares a storage space, GFS is a cluster file system provided by RHCS. multiple nodes mount one file system partition at a time, while the file system data is not damaged, this is a single file system, such as EXT3, EXT2 cannot do.

To enable multiple nodes to perform simultaneous read/write operations on a file system, GFS uses the lock manager to manage I/O operations. When a write process operates on a file, the file is locked, at this time, other processes are not allowed to perform read and write operations, and the lock is released until the write process completes normally. Only after the lock is released can other read and write processes operate on the file. In addition, after a node modifies data on the GFS file system, the modification is immediately visible on other nodes through the underlying communication mechanism of RHCS.

When building a RHCS cluster, GFS is generally used as shared storage and runs on each node. It can be configured and managed through RHCS management tools. The relationships between RHCS and GFS need to be explained. Generally, it is easy for beginners to confuse this concept: Running RHCS, GFS is not necessary, and GFS is required only when shared storage is required, to build a GFS cluster file system, the underlying support of RHCS is required. Therefore, the RHCS component must be installed on the nodes where the GFS file system is installed.

Automated, CLVM

Administrative Tools

WEB management tool luci ricci

Command Line Management Tools: clustat, cman_tool, ccs_tool, fence_tool, and clusvcadm

GFS tools gfs2_fsck, gfs2_tool, gfs2_jadd, gfs2_quota, and gfs2_convert

2. Installation

Yum install cman rgmanager ricci lvm2-cluster gfs2

3. Experiment Architecture

4. initialize luci

192.168.1.155

Luci_admin init

Luci start

Chkconfig -- level 345 luci on

192.168.1.151 chkconfig -- level345 ricci on

192.168.1.152 chkconfig -- level345 ricci on

192.168.1.153 chkconfig -- level345 ricci on

192.168.1.154 chkconfig -- level345 ricci on

5. web configuration https: // 192.168.1.155: 8084

This article from the "Linux O & M history" blog, please be sure to keep this source http://1216621479.blog.51cto.com/7717457/1300121