Oracle 11gR2 RAC 中的 Grid Plug and Play(GPnP) 是什嗎？

 

 

 

一. 什麼是GPnP？

 

Grid Plug and Play (GPnP)：Foundation for a Dynamic Cluster Management 

（1）GPnPeliminates the need for a per node configuration

–It is an underlying gridconcept that enables the automation of operations in the cluster 

–Allows nodes to be dynamicallyadded or removed from the cluster 

–Provides an easier managementto build large clusters OUI does not ask    

–It is the basis for the GridNaming Service (GNS) for a private node name anymore.  

 

（2）Technically,GPnP is based on an XML profile 

–Defining node personality(e.g. cluster name, network classification) 

–Created during installation 

–Updated withevery relevant change (using oifcfg, crsctl) 

–Stored in local files per homeand in the OCR 

- Wallet protected

 

（3） GPnPis apparent in things that you do not  

   see and that youare not asked for (anymore).

 

Grid Plug and Play (GPnP)eliminates per-node configuration data and the need for explicit add and deletenodes steps. This allows a systemadministrator to take a template system image and run it on a new node with nofurther configuration. This removes many manual operations, reduces theopportunity for errors, and encourages configurations that can be changedeasily. Removal of the per-node configuration makes the nodes easierto replace, because they do not need to contain individually-managed state.

    --GPnP 簡化了每個節點的配置資料和添加刪除節點時的一些步驟。也就是說運行系統管理建立模板的系統鏡像，並在新的節點上運行，而不需要其他的配置工作。這樣就減少了一些手工操作，降低了發生錯誤的機率。

 

Grid Plug and Play reduces the cost of installing, configuring, andmanaging database nodes by making their per-node state disposable. It allowsnodes to be easily replaced with regenerated state.

    --GPnP在每個節點通過state來減少安裝，配置和管理資料庫的成本。

 

Grid Plug andPlay enables you to move your data center toward a dynamic grid infrastructure.This enables you to consolidate applications and lower the costs of managingapplications, while providing a highly available environment that can easilyscale when the workload requires.

 

There are manymodifications in Oracle RAC 11g release 2 (11.2) to support the easy additionof servers in a cluster and therefore a more dynamic grid.

 

 

In the past,adding or removing servers in a cluster required extensive manual preparation.With this release, Grid Plug and Play reduces the costs ofinstalling, configuring, and managing server nodes by automating the followingtasks:

--在過去的版本，添加刪除節點需要大量的手工準備，在11gR2中，如下任務通過自動化的操作，GPnP 減少了每個節點安裝，配置和管理伺服器的成本。

 

1)  Adding an Oracle RAC databaseinstance

2)  Negotiating appropriate networkidentities for itself

3)  Acquiring additionalinformation it needs to operate from a configuration profile

4)  Configuring or reconfiguringitself using profile data, making host names and addresses resolvable on thenetwork

 

--查看GPnP的進程：

[root@rac2 ~]# ps -ef|grep gpnp

grid     5124     1  0 15:26 ?        00:00:01/u01/app/grid/11.2.0/bin/gpnpd.bin

root     6646  4954  0 15:38 pts/0    00:00:00 grep gpnp

[root@rac2 ~]#

 

Grid Plug and Play (GPNPD): GPNPD provides access to the Grid Plug and Play profile, andcoordinates updates to the profile among the nodes of the cluster to ensurethat all of the nodes node have the most recent profile.

--GPnPD 進程可以訪問Grid Plug and Play 的profile 檔案，並且在叢集的所有節點中協調更新profile的內容。 已確保所有節點上的GPnP profile是最新的。

 

 

Multicast Domain Name Service (mDNS): Grid Plug and Play uses the mDNS process to locate profiles in thecluster, as well as by GNS to perform name resolution. The mDNS process is abackground process on Linux and UNIX, and a service on Windows.

    --GpnP 使用mDNS 進程來尋找叢集中的profile檔案，然後執行名稱解析。

 

 

The section, AboutPrivate Networks, Network Interfaces, and Network Adapters, says that theentity, Private network interfaces, is stored in the OracleClusterware, in the Grid Plug and Play (GPnP) Profile.

--entity，privatenetwork interface 的資訊也會存入到Oracle Clusterwre 和Grid Plug and Play Profile中。

 

也就是說我們在安裝過程中配置某個interface作為private interface或者使用oifcfg cluster_interconnects命令配置的private interface資訊都會寫入到GPnP的profile中。

 

 

二. GPnP Profile 位置及內容

 

GPnP profile檔案儲存的是叢集的配置資訊。這個XML 檔案裡記錄了如下資訊：

1.網路介面和IP地址(公網和私網)

2.ASM diskstring和spfile資訊

 

注意：Oracle不支援手動修改profile.xml檔案，直接對它的修改可能導致無法修複的問題，最終導致在所有節點重建Clusterware。

 

預設的儲存位置是：

$GRID_HOME/gpnp/$HOSTNAME/profile/peer/profile.xml

$GRID_HOME/gpnp/profile/peer/profile.xml（全域備份）

 

 

在沒有啟動ASM 執行個體之前，diskgroup是沒有mount的，這時候啟動ASM 執行個體必須要讀取spfile檔案。 

 

當ASM instance 尋找初始設定檔案的時候，搜尋的順序如下：

1.  GPnP（Grid Plug and Play） profile 中指定的本地位置

2.  如果GPnP profile中沒有指定初始設定檔案的位置，然後搜尋ASM InstanceHome目錄。這裡會包含2種檔案，SPFILE 和 PFILE，預設路徑是：$ORACLE_HOME/dbs/spfile+ASM.ora

 

在叢集環境下，叢集在啟動的時候,ClusterSynchronization Services (CSS)將掃描所有的ASM disks,它利用的是GPnP profile檔案中的ASM discovery string。

 

在Oracle 10g 的RAC裡面， OCR 和Votingdisk是存放在單獨的raw裝置上的，所以我們可以停止啟動ASM 執行個體。

 

但是在Oracle 11gRAC裡。Oracle 的架構做了變跟。 和ASM 的spfile一樣，OCR和Votingdisk 也存放到了ASM 的磁碟組裡。

 

這時候，在啟動CRS的時候，也必須通過GPnP 屬性檔案來擷取OCR和votingdisk的資訊。 然後在啟動ASM 執行個體和資料庫執行個體。

 

也正式如此，我們在11G RAC環境下，不能停止ASM 執行個體，只能停資料庫執行個體。 ASM 執行個體只能和CRS 一起停止。 因為CRS 依賴的檔案存放在ASM 磁碟組上。

 

 

將profile.xml的內容複寫出來，用瀏覽器開啟，如：

 

 

 

 

 

 

 

 

 

 

 

 

 

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