Frequently Asked Questions

This section contains answers to common questions and recommendations for common issues.

Control Center lost connection to my cluster after restart

The most common case for this is the cluster ID change. It can happen during the restart of an in-memory cluster, or if persistent data storage was lost for a persistent cluster.

If this happened, you can reattach the cluster and continue monitoring it. However, previously collected data and configuration settings will be lost. To avoid losing cluster information, configure a persistent cluster ID on your GridGain cluster.

Preserving Cluster ID

Without a global team:

For this example, we will assume that Control Center is running on http://mydomain.com:3000.

When starting the cluster, you need to prepare secret, cluster id and cluster tag:

Start your cluster and activate.

Run the following commands in this order:

control.bat --property set --name control-center-agent-cluster-secret --val 88f5ea3c-9e50-11ec-b909-0242ac120002 --yes
control.bat --change-id 11111111-1111-1111-1111-111111111111 --yes
control.bat --change-tag prod_cluster --yes
management.bat --uri http://somedomain.com:3000

Use the token command once and attach your cluster:
```
management.bat --token
```

If you lose persistence, next time just run all commands except --token again.

With the global team

First, you need to configure the link:https://www.gridgain.com/docs/control-center/latest/managing/teams/teams#global-teams [global team] in Control Center with the account.globalTeam.enabled and account.globalTeam.attachCluster properties. With it configured, you no longer need to create a token.

Start your cluster and activate it.

Run the following commands in the order you see:

control.sh --property set --name control-center-agent-cluster-secret --val 88f5ea3c-9e50-11ec-b909-0242ac120002 --yes
control.sh --change-id 11111111-1111-1111-1111-111111111111 --yes
control.sh --change-tag prod_cluster --yes

How can I automate connection of clusters to Control Center?

For persistent clusters, you only need to enable the Control Center Global Team by enabling the account.globalTeam.enabled and account.globalTeam.attachCluster properties.

For in-memory clusters, consider adding a small persistent data region. It can be used to store system information, while your caches are still in-memory. If this is not possible, set cluster secret, ID, and other properties after each cluster restart by using the control script. To do this, run the following commands when starting the cluster:

control.sh --property --set --name secret --val UUID
control.sh --change-id UUID

I run Control Center behind SSL proxy. What is the recommended nginx configuration?

Unless you configure your proxy to allow requests through, you will get 403 error when Control Center agents will try to access Control Center server. Here is an example of nginx configuration file that allows for SSL:

upstream <upstream_name> {
     server <control_center_host>:<control_center_port>;
}
server {
  server_name <proxy_server_hostname>;
  listen 9443 ssl;
  ssl_certificate     /etc/nginx/certs/ssl_test_certs/ggcc.crt;
  ssl_certificate_key /etc/nginx/certs/ssl_test_certs/ggcc.nopass.key;
  ssl_protocols       TLSv1.2;
  ssl_ciphers         HIGH:!aNULL:!MD5;
  access_log /var/log/nginx/access.log;
  error_log /var/log/nginx/error.log;
  location / {
    proxy_pass https://<upstream_name>;
    proxy_set_header Host $host;
  }
  location /api/v1 {
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_pass https://<upstream_name>;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  }
  location /socket.io {
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header Host $host;
    proxy_pass https://<upstream_name>;
  }
  location /browsers {
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_pass_header X-XSRF-TOKEN;
    proxy_pass https://<upstream_name>;
    proxy_set_header Origin https://<upstream_name>;
  }
  location /agents {
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_http_version 1.1;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_pass https://<upstream_name>;
  }
}

Control Center monitors Tracing and Compute activity of your cluster; it imposes activity limitations:

Soft limit: When the number or Tracing or Compute messages in the corresponding queue exceeds the "soft" threshold (by default, 200), Control Center attempts to automatically reduce message submission rate for your cluster.

This option is available in GridGain version 8.8.21 and later, in Apache Ignite version 2.14.0.0 and later.
Hard limit: When the number or Tracing or Compute messages in the corresponding queue exceeds the "hard" threshold (by default, 1000), your cluster enters the "limited" state wherein no new Tracing or Compute messages are added to the queues. In all other respects, your cluster remains active and functional. By default, the limited state (a.k.a., "ban") lasts 3 minutes. After that, Control Center checks the status of the Tracing and Compute queues. If it finds that the number of messages diminished below the threshold, the cluster resumes its normal operation. If the number of messages is still above the threshold, the cluster remains in the limited state for another 3 minutes.

To preclude your cluster from entering the limited state, reduce the Tracing percentage for one or more scopes. If this does not help, contact our support.

You can override the default cluster activity thresholds:

Paste the following definitions in the application.yml file:

control.rate-limit.trace-hard-limit = 1000
control.rate-limit.trace-soft-limit = 200
control.rate-limit.compute-hard-limit = 1000
control.rate-limit.compute-soft-limit = 200

Increase threshold values, e.g., from 200 to 500 and/or from 1000 to 2000.

You can also modify the activity limitation parameters:

Add any of the following parameters to the application.yml file:

Parameter	Description	Default Value
control.rate-limit.lower-threshold	Count of requests between the previous and the current checks.	1000
control.rate-limit.update-interval-millis	Frequency of checks in milliseconds.	500
control.rate-limit.ban-duration-seconds	Duration of the ban (the "limited" state) in seconds.	3*60
control.rate-limit.block-connection-on-detection	If "true," the cluster is disconnected instead of entering the "limited" state.	false

Parameter

Description

Default Value

control.rate-limit.lower-threshold

Count of requests between the previous and the current checks.

1000

control.rate-limit.update-interval-millis

Frequency of checks in milliseconds.

500

control.rate-limit.ban-duration-seconds

Duration of the ban (the "limited" state) in seconds.

3*60

control.rate-limit.block-connection-on-detection

If "true," the cluster is disconnected instead of entering the "limited" state.

false

Change the parameter values as required.

My Cache Gets Too Big Too Fast. How Can I Prevent This?

In the Control Center configuration, add the control.repositories.configurations.QuerySessionCache.create-expiration-timeout parameter and set it to a value lower than the default (604800000 seconds, or 7 days). This will reduce the time during which the cache entities (key-value pairs) are accumulated in the cache.

Why do I not receive mail notifications?

GridGain Control Center requires manual configuration of a mailing server to be able to send mail notifications, such as information about teams and shared clusters, or information about alert triggers.

Configuration depends on the specific mailing server you use. The example below will be using MailHog server run in Docker:

Pull MailHog to your local server
```
docker pull mailhog/mailhog
```

Start a container and expose ports to your local ones:

docker run -d -p 1025:1025 -p 8025:8025 mailhog/mailhog

Create an application.properties file in the Control Center root folder and specify mailing server host and port:
```
spring.mail.host=127.0.0.1
spring.mail.port=1024
```

How do I contact support?

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Last updated on Oct 30, 2024