Attach an existing Mirantis Kubernetes Engine cluster¶

Note

The Container Cloud web UI communicates with Keycloak to authenticate users. Keycloak is exposed using HTTPS with self-signed TLS certificates that are not trusted by web browsers.

To use your own TLS certificates for Keycloak, refer to Configure TLS certificates for management cluster applications.

Using the Container Cloud web UI, you can attach an existing Mirantis Kubernetes Engine (MKE) cluster that is not deployed by Container Cloud to a management cluster. This feature allows for visualization of all your MKE clusters details in one place including clusters health, capacity, and usage.

The following table describes the main features and limitations of an existing MKE cluster attached to Container Cloud:

Features	Limitations
Visualize viral cluster details in the Container Cloud web UI such as cluster health, capacity, and usage. Manage cluster permissions. Enable cluster logging, monitoring, and alerting using StackLight. Update the cluster to the latest available Cluster release with the MKE version update, when available. For details, see Update a managed cluster. Enable maintenance mode on the cluster and its machines to perform operating system configuration or node reboot without affecting the workloads. For details, see Enable cluster and machine maintenance mode.	No control over the cluster infrastructure. Container Cloud controls Keycloak integration, reflects the cluster nodes as `Machine` objects, and provides cluster updates. No possibility to add or remove machines, manage operating system configuration (for example, Docker upgrade). The proxy and cache feature is not supported. Nodes of the attached cluster do not contain LCM Agent.

Features

Limitations

Visualize viral cluster details in the Container Cloud web UI such as cluster health, capacity, and usage.
Manage cluster permissions.
Enable cluster logging, monitoring, and alerting using StackLight.
Update the cluster to the latest available Cluster release with the MKE version update, when available. For details, see Update a managed cluster.
Enable maintenance mode on the cluster and its machines to perform operating system configuration or node reboot without affecting the workloads. For details, see Enable cluster and machine maintenance mode.

No control over the cluster infrastructure. Container Cloud controls Keycloak integration, reflects the cluster nodes as Machine objects, and provides cluster updates.
No possibility to add or remove machines, manage operating system configuration (for example, Docker upgrade).
The proxy and cache feature is not supported.
Nodes of the attached cluster do not contain LCM Agent.

For supported MKE versions that can be attached to Container Cloud, see Compatibility matrix of components versions and Support matrix of MKE versions for cluster attachment.

For supported configurations of existing MKE clusters that are not deployed by Container Cloud, see MKE, MSR, and MCR Compatibility Matrix.

Note

Attachment of MKE clusters is tested on the following operating systems:

Ubuntu 20.04
RHEL 7.9
CentOS 8 and 7.9

Note

Using the free Mirantis license, you can create up to three Container Cloud managed clusters with three worker nodes on each cluster. Within the same quota, you can also attach existing MKE clusters that are not deployed by Container Cloud. If you need to increase this quota, contact Mirantis support for further details.

Using the instruction below, you can also deploy StackLight on your existing MKE cluster during the attach procedure. Before that, consider the following:

For StackLight in non-HA mode, make sure that you have the default storage class configured on the MKE cluster being attached. To select and configure a persistent storage for StackLight, refer to MKE documentation: Persistent Kubernetes storage.
Allow the StackLight monitoring agents (Node Exporter and Fluentd) to schedule on the MKE manager and MSR nodes as described in Allow services deployment on Kubernetes MKE manager or MSR nodes.
StackLight requires the capability to create LoadBalancer Services in the cluster to externally expose StackLight web UIs.

For details on StackLight requirements, see StackLight requirements for an MKE attached cluster.

Caution

An MKE cluster can be attached to only one management cluster. Attachment of a Container Cloud-based MKE cluster to another management cluster is not supported.

To attach an existing MKE cluster:

Log in to the Container Cloud web UI with the m:kaas:namespace@operator or m:kaas:namespace@writer permissions.
Switch to the required project using the Switch Project action icon located on top of the main left-side navigation panel.
In the Clusters tab, expand the Create Cluster menu and click Attach Existing MKE Cluster.

In the wizard that opens, fill out the form with the following parameters as required:

Configure general settings:
- Cluster Name - specify the cluster name.
- Region - select the required cloud provider: OpenStack, AWS, Azure, Equinix Metal, vSphere, or bare metal.
Upload the MKE client bundle or fill in the fields manually. To download the MKE client bundle, refer to MKE user access: Download client certificates.
For StackLight, make sure that you have the default storage class configured on the MKE cluster being attached.

To select and configure a persistent storage for StackLight, refer to MKE documentation: Persistent Kubernetes storage.

Configure StackLight:

StackLight configuration¶
Section	Parameter name	Description
StackLight	Enable Monitoring	Selected by default. Deselect to skip StackLight deployment. Note You can also enable, disable, or configure StackLight parameters after deploying a managed cluster. For details, see Change a cluster configuration or Configure StackLight.
	Enable Logging	Select to deploy the StackLight logging stack. For details about the logging components, see Deployment architecture. Note The logging mechanism performance depends on the cluster log load. In case of a high load, you may need to increase the default resource requests and limits for `fluentdLogs`. For details, see StackLight configuration parameters: Resource limits.
	HA Mode	Select to enable StackLight monitoring in the HA mode. For the differences between HA and non-HA modes, see Deployment architecture.
	StackLight Default Logs Severity Level	Log severity (verbosity) level for all StackLight components. The default value for this parameter is Default component log level that respects original defaults of each StackLight component. For details about severity levels, see Log verbosity.
	StackLight Component Logs Severity Level	The severity level of logs for a specific StackLight component that overrides the value of the StackLight Default Logs Severity Level parameter. For details about severity levels, see Log verbosity. Expand the drop-down menu for a specific component to display its list of available log levels.
Elasticsearch	Logstash Retention Time ^{Available since 2.17.0}	Available if you select Enable Logging. Specifies the `logstash-*` index retention time.
	Events Retention Time ^{Available since 2.17.0}	Available if you select Enable Logging. Specifies the `kubernetes_events-*` index retention time.
	Notifications Retention Time ^{Available since 2.17.0}	Available if you select Enable Logging. Specifies the `notification-*` index retention time and is used for Mirantis OpenStack for Kubernetes.
	Retention Time ^{Removed since 2.17.0}	Available if you select Enable Logging. The OpenSearch logs retention period.
	Persistent Volume Claim Size	Available if you select Enable Logging. The OpenSearch persistent volume claim size.
	Collected Logs Severity Level	Available if you select Enable Logging. The minimum severity of all Container Cloud components logs collected in OpenSearch. For details about severity levels, see Logging.
Prometheus	Retention Time	The Prometheus database retention period.
	Retention Size	The Prometheus database retention size.
	Persistent Volume Claim Size	The Prometheus persistent volume claim size.
	Enable Watchdog Alert	Select to enable the Watchdog alert that fires as long as the entire alerting pipeline is functional.
	Custom Alerts	Specify alerting rules for new custom alerts or upload a YAML file in the following exemplary format: - alert: HighErrorRate expr: job:request_latency_seconds:mean5m{job="myjob"} > 0.5 for: 10m labels: severity: page annotations: summary: High request latency For details, see Official Prometheus documentation: Alerting rules. For the list of the predefined StackLight alerts, see Operations Guide: Available StackLight alerts.
StackLight Email Alerts	Enable Email Alerts	Select to enable the StackLight email alerts.
	Send Resolved	Select to enable notifications about resolved StackLight alerts.
	Require TLS	Select to enable transmitting emails through TLS.
	Email alerts configuration for StackLight	Fill out the following email alerts parameters as required: To - the email address to send notifications to. From - the sender address. SmartHost - the SMTP host through which the emails are sent. Authentication username - the SMTP user name. Authentication password - the SMTP password. Authentication identity - the SMTP identity. Authentication secret - the SMTP secret.
StackLight Slack Alerts	Enable Slack alerts	Select to enable the StackLight Slack alerts.
	Send Resolved	Select to enable notifications about resolved StackLight alerts.
	Slack alerts configuration for StackLight	Fill out the following Slack alerts parameters as required: API URL - The Slack webhook URL. Channel - The channel to send notifications to, for example, #channel-for-alerts.

Click Create.

To monitor the cluster readiness, hover over the status icon of a specific cluster in the Status column of the Clusters page.

Once the orange blinking status icon is green and Ready, the cluster deployment or update is complete.

You can monitor live deployment status of the following cluster components:

Component	Description
Bastion	For the OpenStack and AWS-based clusters, the Bastion node IP address status that confirms the Bastion node creation
Helm	Installation or upgrade status of all Helm releases
Kubelet	Readiness of the node in a Kubernetes cluster, as reported by kubelet
Kubernetes	Readiness of all requested Kubernetes objects
Nodes	Equality of the requested nodes number in the cluster to the number of nodes having the `Ready` LCM status
OIDC	Readiness of the cluster OIDC configuration
StackLight	Health of all StackLight-related objects in a Kubernetes cluster
Swarm	Readiness of all nodes in a Docker Swarm cluster
LoadBalancer	Readiness of the Kubernetes API load balancer
ProviderInstance	Readiness of all machines in the underlying infrastructure (virtual or bare metal, depending on the provider type)

For StackLight, add the StackLight label to worker nodes. For details, see Node Labels in Create a machine using web UI.
1. On the Machines page, click the More action icon in the last column of the required machine field and select Configure machine.
2. In Node Labels, select StackLight.

Caution

To detach an MKE cluster, use the Detach button in the cluster menu of the Container Cloud web UI. Do not delete the cluster machines using the cloud provider tools directly to prevent issues with cluster detachment or cleaning of machines resources manually.