RAC User Equivalence Check Failed

在使用SSH方式配置RAC時，可能會在檢查使用者等價時失敗。

配置了SSH之後，發現在驗證使用者等價時失敗：

$ ./runcluvfy.sh comp nodecon -n ahrac1,ahrac2 -verbose

Verifying node connectivity

ERROR:
User equivalence unavailable on all the nodes.
Verification cannot proceed.

Verification of node connectivity was unsuccessful on all the nodes.

查詢metalink發現是Oracle cluvfy工具的問題。Oracle在文章：Note:369598.1：User Equivalence Check Failed for User Oracle Using Ssh/scp中進行了詳細的描述。

簡單的說，Oracle在尋找ssh命令時，去/usr/local/bin目錄下尋找，而ssh命令在/usr/bin目錄下。

相應的解決方法也很簡單，在/usr/local/bin目錄下建立一個指向/usr/bin/ssh的連結就可以了。

root@ahrac1 # mkdir -p /usr/local/bin
root@ahrac1 # ln -s -f /usr/bin/ssh /usr/local/bin/ssh
root@ahrac1 # ln -s -f /usr/bin/scp /usr/local/bin/scp

不過再次嘗試，仍然報錯：

$ ./runcluvfy.sh comp nodecon -n ahrac1,ahrac2 -verbose

Verifying node connectivity

ERROR:
User equivalence unavailable on all the nodes.
Verification cannot proceed.

Verification of node connectivity was unsuccessful on all the nodes.

後來才發現，原來Oracle使用者的ssh驗證步驟必須先執行：

$ exec /usr/bin/ssh-agent $SHELL
$ /usr/bin/ssh-add
Enter passphrase for /export/home/oracle/.ssh/id_rsa:
Identity added: /export/home/oracle/.ssh/id_rsa (/export/home/oracle/.ssh/id_rsa)
Enter passphrase for /export/home/oracle/.ssh/id_dsa:
Identity added: /export/home/oracle/.ssh/id_dsa (/export/home/oracle/.ssh/id_dsa)
$ ./runcluvfy.sh comp nodecon -n ahrac1,ahrac2 -verbose

Verifying node connectivity

Checking node connectivity...

Interface information for node "ahrac2"
Interface Name IP Address Subnet
------------------------------ ------------------------------ -----------
ce0 172.25.198.43 172.25.0.0
ce0 172.25.198.45 172.25.198.0
ce1 10.0.0.4 10.0.0.0

Interface information for node "ahrac1"
Interface Name IP Address Subnet
------------------------------ ------------------------------ -----------
ce0 172.25.198.42 172.25.0.0
ce0 172.25.198.44 172.25.198.0
ce1 10.0.0.3 10.0.0.0

Check: Node connectivity of subnet "172.25.0.0"
Source Destination Connected?
------------------------------ ------------------------------ -----------
ahrac2:ce0 ahrac1:ce0 yes
Result: Node connectivity check passed for subnet "172.25.0.0" with node(s) ahrac2,ahrac1.

Check: Node connectivity of subnet "172.25.198.0"
Source Destination Connected?
------------------------------ ------------------------------ -----------
ahrac2:ce0 ahrac1:ce0 yes
Result: Node connectivity check passed for subnet "172.25.198.0" with node(s) ahrac2,ahrac1.

Check: Node connectivity of subnet "10.0.0.0"
Source Destination Connected?
------------------------------ ------------------------------ -----------
ahrac2:ce1 ahrac1:ce1 yes
Result: Node connectivity check passed for subnet "10.0.0.0" with node(s) ahrac2,ahrac1.

Suitable interfaces for the private interconnect on subnet "172.25.0.0":
ahrac2 ce0:172.25.198.43
ahrac1 ce0:172.25.198.42

Suitable interfaces for the private interconnect on subnet "172.25.198.0":
ahrac2 ce0:172.25.198.45
ahrac1 ce0:172.25.198.44

Suitable interfaces for the private interconnect on subnet "10.0.0.0":
ahrac2 ce1:10.0.0.4
ahrac1 ce1:10.0.0.3

ERROR:
Could not find a suitable set of interfaces for VIPs.

Result: Node connectivity check failed.

Verification of node connectivity was unsuccessful on all the nodes.

至此，問題得到解決。