Server: IBM, CentOS, Kubernetes, and More
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IBM's 'bare metal' LinuxONE push: Did somebody say OpenShift?
Red Hat has released betas of RHEL 8.7 and 9.1 while its parent company IBM is offering Linux mainframe instances in the cloud, although only in some regions.
If you're looking for some particularly resilient home in the cloud to run Linux workloads, Red Hat's parent company IBM has a new mainframe-based Infrastructure-as-a-Service product out under the LinuxONE umbrella, which it has dubbed "bare metal servers."
As we described a few years ago, IBM offers a whole range of different hypervisors on mainframes, including PR/SM (akin to a hypervisor in the firmware) and the native Linux in-kernel hypervisor KVM. One of the company's flagship mainframe OSes, z/VM, is perhaps more commonly used to manage VMs on Z series, but it's cheaper to rent LinuxONE mainframes because they've been tweaked to only run Linux, excluding any native IBM mainframe OSes.
It's noticeable that the announcement specifically mentions Red Hat's container management platform OpenShift – maybe not unrelated to Red Hat's new CEO Matt Hicks, who was one of the original OpenShift team.
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CentOS Hyperscale SIG conference recap - Blog.CentOS.org
In the past couple of months members of the CentOS Hyperscale SIG attended several conferences where they were able to share the work the SIG is doing and meet up in person, in some cases for the first time.
We have a page tracking conference presentations around Hyperscale-related topics. You can find references there to all talks mentioned below, including video recordings where available.
Conferences aren’t just about presentations though. The “hallway track” provides a great opportunity for serendipidous connection, and the various social events are often a great venue for folks to mingle and get to know each other in an informal setting.
If you’d like to meet us in person at a future event please reach out. We also generally cover conferences we plan to attend in our quarterly reports.
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Enforce CRD Immutability with CEL Transition Rules
Immutable fields can be found in a few places in the built-in Kubernetes types. For example, you can't change the .metadata.name of an object. Specific objects have fields where changes to existing objects are constrained; for example, the .spec.selector of a Deployment.
Aside from simple immutability, there are other common design patterns such as lists which are append-only, or a map with mutable values and immutable keys.
Until recently the best way to restrict field mutability for CustomResourceDefinitions has been to create a validating admission webhook: this means a lot of complexity for the common case of making a field immutable.
Beta since Kubernetes 1.25, CEL Validation Rules allow CRD authors to express validation constraints on their fields using a rich expression language, CEL. This article explores how you can use validation rules to implement a few common immutability patterns directly in the manifest for a CRD.
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Exploring the Benefits of Containerization - Container Journal
As part of the effort to simplify application development processes, many developers are leveraging containerization. It is one way of grouping the infrastructure of applications, making it easier for developers to interact with and manage. It’s not a new method and has been evolving for several years now, allowing developers to become more confident in using it. Containerization also has many benefits for developers.
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The Growing Appreciation for Service Mesh