Agents Administration - Tests
 

Configuration of RedisClstrFailoverTest

This test continuously monitors all the nodes in the cluster and promptly alert administrators if failover occurred. In addition, the administrators can identify the details of changed roles of the nodes in the cluster using the detailed diagnosis.

The default parameters associated with this test are:

  • The TEST PERIOD list box helps the user to decide how often this test needs to be executed.

  • In the HOST text box, specify the IP address of the target server that is being monitored.

  • Specify the port to which the specified host listens in the PORT text box.

  • USERNAME parameter is applicable only if the target server is Redis v6 or above. The eG agent has to be configured with the credentials of a user who has Read-only privileges on the monitored Redis Cluster Server. To create a user named eguser,run the following command.

    acl setuser <username> on ><passowrd> allcommands allkeys

    For example, to create a eguser with read only privilege run the following command:acl setuser eguser allkeys -@all +client|list +cluster|info +cluster|nodes +config|get +info +memory|usage +ping +scan +slowlog|get +time +ttl +xinfo|groups +xinfo|stream resetchannels on >password

  • For Redis v6 or above, provide the password for the above mentioned user in the Redis Password textbox. Then, confirm the password by retyping it against CONFIRM PASSWORD.Before v6, Redis did not include the notion of users, and the only authentication strategy was a single login password. In some high security environments, a password may have been set for the Redis server, so as to protect it from unauthorized accesses/abuse. If such a password has been set for the monitored Redis server, then specify that password against REDIS PASSWORD. Then, confirm the password by retyping it against CONFIRM PASSWORD.

      If the Redis server is not password protected, then do not disturb the default setting of this parameter.

      To determine whether/not the target Redis server is password-protected, do the following:

    • Login to the system hosting the Redis server.

    • Open the redis.conf file in the <REDIS_INSTALL_DIR>.

    • Look for the requirepass parameter in the file.

    • If this parameter exists, and is not preceded by a # (hash) symbol, it means that password protection is enabled for the Redis server. In this case, the string that follows the requirepass parameter is the password of the Redis server. For instance, say that the requirepass specification reads as follows:

      requirepass red1spr0

      According to this specification, the Redis server is protected using the password red1spr0. In this case therefore, you need to specify red1spr0 against REDIS PASSWORD.

    • On the other hand, if the requirepass parameter is prefixed by the # (hash) symbol as shown below, it means password protection is disabled.

      # requirepass red1spr0

      In this case, leave the REDIS PASSWORD parameter with its default setting.

  • By default, the SSL flag is set to No, indicating that the target Redis cluster server is not SSL-enabled by default. To enable the test to connect to an SSL-enabled Redis cluster server, set the SSL flag to Yes.

  • By default, the CLUSTER NODES parameter is set to auto-discover, indicating that, by default, this test will auto-discover the nodes available in the cluster and report metrics for all the discovered nodes. However, in case of node failures the eG agent needs to connect to any of the available nodes and collect metrics. To this effect, provide a comma-seperated list of nodes in this text box. You should specify the nodes in the following format: HOSTNAME1#PORT1,HOSTNAME2#PORT2,... . For example, 172.16.8.81#30071,172.16.8.81#30072,....

  • Often, administrators find it difficult to identify the problematic nodes at a single glance in a cluster, in environments where hundreds of nodes are available. To easily identify the problematic nodes, administrators are allowed to group the nodes into master and its respective replicas under a group name (prefix). To this effect, the MASTER SLAVE GROUP flag is set to Yes, by default indicating that this test will report metrics for each group name (prefix):node name combination i.e., the descriptor of this test will be group name (prefix):node name. If you do not wish to group the nodes, then, set this flag to No in which case, the descriptor of the test will be the nodes. 

  • The MASTER SLAVE GROUP PREFIX parameter is applicable only if the MASTER SLAVE GROUP flag is set to YES. In this text box, specify the name of the prefix under which the nodes should be grouped. For example, if the nodes are to be grouped with a  prefix Shard, then, the descriptors of this test will be displayed in the following format: Shard1:<comma-separated list of node names>, Shard2: <comma-separated list of node names>, ...

  • DD FREQUENCY refers to the frequency with which detailed diagnosis measures are to be generated for this test. The default is 1:1. This indicates that, by default, detailed measures will be generated every time this test runs, and also every time the test detects a problem. You can modify this frequency, if you so desire. Also, if you intend to disable the detailed diagnosis capability for this test, you can do so by specifying none against DD FREQUENCY.

  • To make diagnosis more efficient and accurate, eG embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test, by default, for a particular server, choose the On option against DETAILED DIAGNOSIS. To disable the capability, click on the Off option.

    The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled:

    • The eG manager license should allow the detailed diagnosis capability.

    • Both the bad and normal frequencies configured for the detailed diagnosis measures should not be 0.

  • If multiple components of the same component type are awaiting configuration, then an APPLY TO OTHER COMPONENTS button will appear in this page. Clicking on this button will allow you to apply the configuration to all/selected components of that type.

  • Once the necessary values have been provided, clicking on the UPDATE button will register the changes made.

When changing the configuration for specific servers, a “*” beside the text box corresponding to the parameter signifies that these values have to be manually configured by the user. The parameter values that require to be configured will typically be prefixed with a “$” or contain a series of “*”. A value of “none” in the parameter value indicates that the corresponding parameter value can be changed if required.