The following sequence diagram describes the high level steps that are carried out in a sequence during the provisioning process. Customers can optionally automate the entire sequence using the RCTL CLI or REST APIs or automation tools.
Watch a video of provisioning of a "Multi Master" upstream Kubernetes cluster on "CentOS" with only Storage for persistent volumes.
STEP 1: Select Cluster Configuration¶
Review the supported cluster configurations and select your desired cluster configuration. This will determine the number of nodes you need to prepare to initiate cluster provisioning.
|Type||Number of Initial Nodes|
|Converged, Single Master||1 Nodes (1 Master/Worker)|
|Dedicated, Single Master||2 Nodes (1 Master + 1 Worker)|
|Converged, Multi Master||3 Nodes (3 Masters + 1 Worker)|
|Dedicated, Multi Master||4 Nodes (3 Masters + 1 Worker)|
STEP 2: Prepare Nodes¶
Create VMs or bare metal instances compatible with the infrastructure requirements.Ensure that you have SSH access to all the instances/VMs
Ensure you have the exact number of nodes for initial provisioning as per the cluster configuration from the previous step. Additional worker nodes can be added after the cluster is successfully provisioned.
STEP 3: Create a Cluster¶
- Login into the Console
- Navigate to the Project where you would like the cluster provisioned.
- Click on New Cluster
- Select "Create a New Cluster" and click Continue
- Select "Environment" as "Data center/Edge"
- Select "Linux Installer"
- Give it a name and click Continue
A number of defaults are automatically selected and presented. A number of options are available for customization
- Specify a location for the cluster (for multi cluster workflows)
- Select cluster blueprint and version
- Select the Kubernetes version that you want to deploy
- Select the OS and Version you used for the nodes
- If you require distributed storage, select GlusterFS
- If you have selected multiple storage types, select the default storage class.
By default, as a security precaution, nodes need to be approved before it is allowed to join a cluster. Auto Approval of nodes is available and this can help streamline the cluster provisioning and expansion workflows.
- Enable "Approve Nodes Automatically" if you do not require an approval gate for nodes to join the cluster
- Select Multi Master if you need a highly available k8s master configuration
- Select Dedicated Master if want the k8s masters to be tainted to not allow workload pods
Select "Enable Proxy" if the infrastructure being used to provision the cluster is behind a forward proxy.
Configure the http proxy with the proxy information (ex: http://proxy.example.com:8080)
- Configure the https proxy with the proxy information (ex: http://proxy.example.com:8080)
- Configure No Proxy with Comma separated list of hosts that need connectivity without proxy
- Configure the Root CA certificate of the proxy if proxy is terminating non MTLS traffic
- Enable "TLS Termination Proxy" if proxy is terminating non MTLS traffic and cannot provide the Root CA certificate of the proxy.
Proxy configuration cannot be changed once the cluster is created.
Default subnet used for pod networking is "10.244.0.0/16" Default subnet used for k8s services is "10.96.0.0/12"
If you want to customize the subnets used for Pod Networking and K8s Services:
- Configure the "Pod Subnet" with the subnet that you want to use.
- Configure the "Service Subnet" with the subnet that you want to use.
Cluster Networking cannot be changed once the cluster is created.
STEP 4: Download Conjurer and Secrets¶
- Review the Node Installation Instructions section on the Console
- Download the cluster bootstrap binary (i.e. Conjurer)
- Download the cluster activation secrets (i.e. passphrase and credential files)
- SCP the three (3) files to the nodes you created in the previous step
Note that the activation secrets (passphrase and credentials) are unique per cluster. You cannot reuse this for other clusters.
An illustrative example is provided below. This assumes that you have the three downloaded files in the current working directory. The three files will be securely uploaded to the “/tmp” folder on the instance.
$ scp -i <keypairfile.pem> * ubuntu@<Node's External IP Address>:/tmp
STEP 5: Preflight Checks¶
It is strongly recommended to perform the automated preflight tests on every node to ensure that the node has "compatible" hardware, software and configuration. View the detailed list of preflight checks.
- SSH into the node and run the installer using the provided passphrase and credentials.
- From the node installation instructions, copy the preflight check command and run it
- If there are no errors, proceed to the next step
- If there are warnings or errors, fix the issues, run the preflight check before proceeding to the next step
STEP 6: Run Conjurer¶
- From the node installation instructions, copy the provided command to run the conjurer binary
- SSH into the nodes and run the installer using the provided passphrase and credentials.
An illustrative example provided below
sudo ./conjurer -edge-name="onpremcluster" -passphrase-file="onpremcluster-passphrase.txt" -creds-file="onpremcluster.pem -t [+] Initiating edge node install [+] Provisioning node [+] Step 1. Installing node-agent [+] Step 2. Setting hostname to node-72djl2g-192-168-0-20-onpremcluster [+] Step 3. Installing credentials on node [+] Step 4. Configuring node-agent [+] Step 5. Starting node-agent [+] Successfully provisioned node
Conjurer is a “cluster bootstrap agent” that connects and registers the nodes with the Controller. Information about the Controller and authentication credentials for registration is available in the activation secrets files.
- Once this step is complete, the node will show up on the Web Console as DISCOVERED.
STEP 7: Approve Node¶
This is an optional approval step that acts as a security control to ensure that administrators can inspect and approve a node before it can become part of the cluster.
- Click on Approve button to approve the node to this cluster
- In a few seconds, you will see the status of the node being updated to “Approved" in the Web Console
- Once approved, the node is automatically probed and all information about the node is presented to the administrator on the Web Console.
STEP 8: Configure Node¶
This is a mandatory configuration step that allows the infrastructure administrator to specify the “role” for the node.
Without the configuration step, cluster provisioning cannot be initiated.
- Click on Configure
- If the node is meant to be a k8s master, select "master" role
- If the node is meant to handle storage, select the storage location from the automatically detected list
- Select the network interface that will be used for cluster networking from the automatically detected list of interfaces
- Click Save
STEP 9: Provisioning¶
At this point, we have provided everything necessary where the Controller can start provisioning Kubernetes and all required software add-ons. These will be automatically provisioned and configured to operationalize the cluster.
- Click on Provision
- A progress bar is displayed showing progress as the software is downloaded, installed and configured on all the nodes.
The end-to-end provisioning process can take time and is dependent on the number of nodes you are provisioning and the Internet bandwidth available to your nodes to download necessary software.
Once the "minion/node agent" installed on the node by conjurer successfully and is registered with the controller, it establishes a "long running" web socket with the controller providing "continuous updates" to the controller about progress and status. This information is then presented to authorized administrators via the Console for insights. Optionally, administrators can also view the logs generated by the minion/node agent for detailed visibility.
tail -f /var/log/salt/minion
View Cluster Configuration¶
Administrators can view the provisioned cluster's configuration by clicking on the cluster and selecting the "Configuration" tab.
Althought "conjurer" provides a built in battery of "preflight tests" that can be used to verify the environment and configuration, there are some scenarios where provisioning can fail.
If your instances (for the nodes) have a host firewall such as firewalld or iptables rules, it may be silently dropping all packets destined for the Controller. This will result in provisioning failure. Ensure that the host firewall is configured to allow outbound communications on tcp/443 to the controller.
The Maximum Transmission Unit (MTU) is the largest block of data that can be handled at Layer-3 (IP). MTU usually refers to the maximum size a packet can be. Certain MTU/MSS settings can result in fragmentation related issues with mTLS connections between the agents and the controller.
Unstable or unreliable network connectivity. Remote cluster provisioning in remote, low bandwidth locations with unstable networks can be very challenging. Please review how the retry and backoff mechanisms work by default and how they can be customized to suit your requirements.