Shulou(Shulou.com)06/03 Report--

Recently, Rancher Labs, the world's leading provider of container management software, announced the full release of its flagship Rancher-- open source enterprise Kubernetes management platform, the latest version of Rancher 2.2 Preview 2, which contains many powerful features operating in K8S clusters.

You can learn about the new features released by visiting the release page (https://rancher.com/products/rancher/2.2/) and release notes (https://github.com/rancher/rancher/releases/tag/v2.2.0-alpha6).

This article will introduce one of the features: multi-cluster applications (multi-cluster applications), which will show you how this feature will significantly reduce your workload and improve the reliability of multi-cluster operations.

An overview

If you have used k8s and have two or more cluster operation and maintenance experience, you will encounter the following situation:

When deploying (AZs) across multiple availability zones, applications need to be more fault tolerant

In an edge computing scenario with hundreds of clusters, the same application needs to run on multiple clusters.

In the case of high reliability, operators usually reduce the risk of unavailability of a single availability zone by integrating nodes from multiple availability zones into a cluster. But the problem of this scheme is that although it can resist the failure of the availability zone, it can not prevent the failure of the cluster itself, and the possibility of the failure of the cluster is higher than that of the availability zone, and once the cluster fails, it may affect the programs running in the cluster.

Another way is to run a separate cluster in each availability zone, with a copy of the application running on each cluster. This is equivalent to a set of k8s clusters in each availability zone, but each cluster is expensive and error-prone to maintain applications manually.

Edge computing scenarios have the same problem as multi-availability zone clusters: manual maintenance of the application is time-consuming and error-prone. Even if the operation and maintenance team creates complex scripts to deploy and upgrade, there is another point of failure. Moreover, these scripts also need to be upgraded and maintained, and the responsible operation and maintenance personnel are required not only to write the process (upgrade and release process), but also to be able to turn to human operation and maintenance if the script fails.

Starting with Rancher 2.2 Preview 2 (https://github.com/rancher/rancher/releases/tag/v2.2.0-alpha6), Rancher supports simultaneous deployment and upgrade of copies of the same application in any number of K8s clusters.

The Helm package Manager-based Application Store (Application Catalogs) has also been extended. Previously, the App Store was only available for a single cluster, and we added an additional feature at the global level to deploy applications to any cluster managed by Rancher if permissions permit.

Please stay tuned for a complete demonstration of the features of Rancher 2.2 Preview2. We will launch a new season of online training in March, when we will provide a demonstration of the new features and answer questions in the Quan A session.

The following will demonstrate how to easily manage multi-cluster applications in Rancher.

Getting started with featur

After logging in to Rancher, you will see a list of all the clusters managed, and add a button for "Multi-Cluster applications (Multi-Cluster Apps)] in the menu bar.

After clicking the multi-cluster application button, you will see two buttons, [manage Catalogs] and [start]. [manage Catalogs] will skip to the management page of [App Store (Catalogs)], where you open source to enable major Helm repo or add other third-party Helm repo.

Click the start button to start the new application.

From the deployable applications shown, select Grafana (for demonstration).

Configure the details as required, using the form or directly with the YAML provided. Note that the settings here will be applied to the cluster where this application is deployed.

Under "configuration options", select the specified project of the target cluster in the [Target (target)] drop-down box.

Select the upgrade strategy. For demonstration here, we will select [Rolling Update] and provide 1 per batch at an interval of 20 seconds. This setting ensures that only one cluster is updated at a time when the application is upgraded later, and that each cluster upgrade operation is 20 seconds apart.

If you want to adjust the differences between clusters, you can set them in the [Answer Overrides] section.

Everything is ready, click [start] at the bottom, and then jump to the results page, showing the multi-cluster application that has just been installed (here is the Grafana for the demonstration). Each application will display the current status and target cluster as well as a list of projects.

When the application can be upgraded, the application status will display [Upgrade Available].

To start the upgrade, click the menu button (three-point menu) on the application, and then select upgrade.

Verify that the Roll Update option is selected.

Change some settings, and then click the upgrade button at the bottom.

Open the workload tab of the target cluster, and you will see that one of the status changes to update, and the application in this cluster will be updated, and then Rancher will pause for 20s (the interval just set), and then continue to update the application of the next cluster.

Total knot

Multi-cluster applications will reduce the workload of the operation and maintenance team and make it possible to deploy and upgrade applications quickly and reliably across clusters.

To test these features in a lab or development environment, install the latest version of Alpha (https://rancher.com/docs/rancher/v2.x/en/installation/server-tags/#helm-chart-repositories), and if you have any feedback, please submit Issues on Github or join the forum (https://forums.rancher.com/) or Slack (https://slack.rancher.io/)). Click [read the original text] at the end of the article to enter the Github interface and mention issue.

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