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Node Attribute
Node attribute can be identified from NodeAttributes view of MCCS console.
From the node management view of MCCS console, select node, then select the ‘Node Attributes’ tab located on right top of detailed information panel.
The values of gray colored are for read only. They just contain and show the information of node state. The values of white colored are configurable by user definition. Below is description of some of them.
[그림] 노드 속성 화면Figure] Node Attribute View
Attribute | Description | Type | Default | Edit | Note |
| BootMode | It is value that indicate whether auto-start or not to been started according to the bootMode value setting when MCCS service starts.. | BOOLEAN | X | ||
| ExpirationDate | It shows license MAC of the node. | STRING | |||
| HostID | It shows license MAC of the node. | STRING | X | ||
| IsolationTestAddressIsolationTestAddresses | It enters the IP address to test Isolation. It is recommended the reliable IP address. | IP ADDRESS | O | ||
| LicenseType | It shows license type of the node. | STRING | X | ||
NodeName | It indicated the name of the node. | NAME |
| X | |
NodeState | It indicated the state of the node. | STRING |
| X | |
PrimaryHB | It shows an IP address of the Primary Heartbeat defined in the MCCS server. | IP ADDRESS |
| X | |
| PrimaryHBStatus | It indicates state of primary heartbeat | IP ADDRESS | X | ||
SecondaryHB | It shows an IP address of the Secondary Heartbeat defined in the MCCS server. | IP ADDRESS |
| X | |
| SecondaryHBStatus | It indicates state of secondary heartbeat | IP ADDRESS | X | ||
| StandAlone | It indicates whether standalone mode or not. | BOOLEAN | false | X |
How MCCS Works
MCCS connects nodes as one cluster through heartbeat connection.
Action of the cluster is decided by the state and role of the node, and node states are decided not only by the system state but also the state of heartbeat connection.
Following are node states for Cluster Mode.
Node states of the Cluster Mode
Node states of the Cluster Mode
| State | Description |
|---|---|
| EXITED | This is a state where MCCS engine is terminated.. |
| INITING | This is a state before configuring the heartbeat after starting the engine. This is initial state before both nodes communicate each other through heartbeat network and collect mutual status of node state after MCCS engine is started. This state is normally changed to the LOCAL_BUILD or REMOTE_BUILD state, but if there is a problem with the configuration or physical environment, it remains in the INITING state, or is automatically terminated to the EXITED state. |
| LOCAL_BUILD | When every node in the cluster is in the INITING state, the node with the highest priority at establishing of heartbeat communication is changed to the LOCAL_BUILD state, and the node in this state forms a cluster database from the local configuration file(%MCCS$MCCS_HOME%\HOME/config\/main.json). Only one node within the cluster goes through this state to the RUNNING state, and other nodes undergo the REMOTE_BUILD state that receives information from that node. |
| REMOTE_BUILD | When a node in the INITING state detects a node in the RUNNING state through heartbeat communication, it establishes by downloading the configuration |
| RUNNING | This is the state when establishing a configuration database through the LOCAL_BUILD or REMOTE_BUILD is completed, and starts agents and group administrators of all the resources defined at this state. |
| FAULTED | When all the heartbeats with the node in the RUNNING state are disconnected, the node is FAULTED. |
Action step according to Node State
Following is the process of the change of the node state of MCCS.
[Figure] MCCS Action step according to Node State
Redundancy of heartbeat communication path
Heartbeat has the vital role of synchronizing the state and determining the failure state between nodes.
Therefore, when the system is being operated, it must be redundant to guarantee a state of being available for communication at all times.
Also, to determine the isolation of the network, one of the heartbeat networks must be established as a network available for communication with the service network or nodes other than the cluster node.
Node Fault
When all the heartbeat communication is disconnected for a certain amount of time, the node is declared to be in failure state.
The final decision on the discontinuance of heartbeat communication is made by the ICMP test.
When both nodes cannot communicate with each other within a defined amount of time, MCCS define the state as split, isolation and remote node fault.
Discontinuance of heartbeat
If all of the heartbeat communication is disconnected, both nodes cannot exchange the mutual state.
Service recovery and process are determined by whether the opposite node is declared as a failure, or simply in a state in which the communication paths between nodes are disconnected.
Split Brain
핫빗 네트워크의 단절이 클러스터 속성에 정의되어 있는 일정 시간 간격 이상의 시간차로 발생할 경우는 노드 장애 보다는 핫빗 네트워크 전체에 대한 불안정을 의심할 수 있습니다If the interval of heartbeat network disconnections is greater than the limit set in the cluster attribute, you can suspect instability of the entire heartbeat network instead of node failures.
Thus, it is deemed that the heartbeat node status cannot be trusted and it does not detect system failures but maintains the current status.
When heartbeat communication is restored, the nodes in the clusters will restart the MCCS service and return to the running status.
그렇지 않으면 INITING 상태에서 핫빗 통신이 정상화될 때까지 대기하게 됩니다.
Isolation
일정 시간 내에 모든 핫빗이 단절된 경우라도 상대 노드를 장애로 판단하기 전에 먼저 로컬 노드 자신이 모든 네트워크로부터 단절된 상황인지를 확인할 필요가 있습니다.
만일 게이트웨이 혹는 DNS 서버와 같이 공인된 네트워크 지점과의 통신이 가능한 상태라면 로컬 노드 자신은 단절된 상황은 아니며, 상대 노드가 장애 상태인 것으로 판단하여 상대 노드에서 운영중인 서비스의 복구를 시도할 수 있습니다.
그러나 그렇지 않은 경우에는 상대 노드가 로컬 노드의 상황을 고립으로 판단합니다.
상대 노드는 로컬 노드를 장애 상태로 결정하고, 로컬에서 운영중인 서비스에 대한 복구를 시도하기 때문에, 로컬 노드는 가능한 빨리 운영중인 서비스를 종료해야 합니다If not, it will wait until heartbeat communication is restored in INITING state.
Isolation
Before declaring the opposite node as a failure even when all the heartbeats are disconnected within a certain time period, MCCS check the local node is disconnected from the whole network.
If the node can communicate to authorized network points such as gateway or DNS server, the local node is not disconnected, and it can be concluded that the opposite node is in a failure state and will not try to recover.
It that is not the case, it can be considered as isolation state.
Since standby node considers local node has a failure while local is trying to recover the service, service on local node needs to be terminated as soon as possible.
Remote Node Fault
When a local node cannot communicate to opposite node within a defined timeout and it is not in an isolation state, local node will try to keep its state as RUNNING, and bring ONLINE the services which taken OFFLINE from remote node.
How to Change the Node Name
- In the web console, select the node management view and select the node to change the name for.
[Figure] Node Name Change Selected
CLI 사용(mcnode 명령)
노드에 관한 명령을 전달 합니다. 노드에 대해 속성 조회, 속성 값 변경, 라이선스 입력, 서포트 파일 다운로드 명령을 내릴 수 있습니다.
...
- Enter the node name to change.
[Figure] New Node Name Input - In the web console's node management view,
you can check the newly changed node name.
CLI Use(mcnode command)
It sends the node commands. You can command to inquire about or change the node attributes, enter the license or download the support file.
| Info |
|---|
When you install MCCS, the initial user account ID is set to 'admin' and the password is set to 'password'. |
Syntax
| Code Block |
|---|
mcnode [-u userid -pw password] [-n nodename] [-a attribute] [-l license] [-p download_path] |
Options
| 옵션Option | 설명Description |
-h | 도움말을 출력합니다Display Help. |
| -u | 사용자 계정을 지정합니다Designate the user account ID. |
| -pw | 사용자 Password를 지정합니다Enter user password. |
-n | 명령을 실행하기 위해 접근할 노드를 지정합니다Designate a node to be accessed to run the command. |
-a | If the [modify] 명령일 경우 변경할 속성과 속성값을 지정합니다command is used, set the attribute and the attribute values to change. |
-p | 서포트 파일 다운 받을 경로를 지정합니다. path 지정 생략시 user.home으로 다운로드 됩니다Designate the path for downloading the support file. If you do not enter the path, it will be downloaded to 'user.home'. |
| -l | 지정한 노드의 입력할 라이선스 값을 지정합니다Enter the license value to be entered for the designated node. |
Example
modify
Modify the attribute values for testNode-1의 노드 속성값을 수정합니다1.
| Code Block |
|---|
mcnode -u admin -pw password -modify -n testNodeTestNode-1 -a IsolationTestAddressattribute attribute_value |
license
Enter the license for testNode-1 노드의 라이선스를 입력합니다.
| Code Block |
|---|
mcnode -u admin -pw password -license -n TestNode-1 [ -all ] license_value |
support
Download the support file of testNode-1 노드의 서포트 파일을 to /root/Desktop/mantech 에 다운로드 받습니다.
(-all 입력시 노드 전체에 대하여 서포트파일을 생성 후 다운로드 합니다If you enter -all, it will create the support file for all the nodes and then download them.)
| Code Block |
|---|
mcnode -u admin -pw password -supprot [-n TestNode-1 ([ -all) ] -p /root/Desktop/mantech |
list
노드의 속성 리스트를 보여줍니다.
(noname 입력시 입력한 해당 노드에 대한 속성 값만 출력Show the list of node attributes.
(If you enter node name, it will only display the attribute values for the node entered.)
| Code Block |
|---|
mcnode -u admin -pw password -list ([-n nodename)] |