OpenShift al­ter­na­tives

OpenShift is the leading de­vel­op­ment platform for con­tainer­ized ap­pli­ca­tions based on Ku­ber­netes. A growing number of companies are using Ku­ber­netes as a cluster manager as a basis for operating and de­vel­op­ing con­tainer­ized ap­pli­ca­tions and services. In other words, Ku­ber­netes is a dis­trib­uted operating system for modern, container-based de­vel­op­ment.

The OpenShift platform was released by Red Hat – the maker of the pro­fes­sion­al Linux dis­tri­b­u­tion “Red Hat En­ter­prise Linux” (RHEL). The OpenShift al­ter­na­tive “Rancher” has now been taken over by the tra­di­tion­al Linux provider SUSE. “Canonical Ku­ber­netes”, is another OpenShift al­ter­na­tive from an es­tab­lished Linux provider. Read on to find out more about these and other al­ter­na­tives to OpenShift.

OpenShift is a powerful system that combines a variety of func­tion­al­i­ties. In addition to Ku­ber­netes man­age­ment, it includes a dashboard to visualize clusters. Tools for mon­i­tor­ing and logging, DevOps pipelines and a service mesh round out its functions that make it easy to set up dis­trib­uted ap­pli­ca­tions and services. In summary, OpenShift and its al­ter­na­tives are Ku­ber­netes man­age­ment solutions.

Ku­ber­netes are the common feature of OpenShift and its al­ter­na­tives. But their functions extend far beyond managing con­tainer­ized ap­pli­ca­tions. In contrast to bare Ku­ber­netes, OpenShift and al­ter­na­tives control de­ploy­ment and operation of dis­trib­uted Ku­ber­netes clusters across the cloud and other in­fra­struc­tures. Thanks to user end-to-end au­then­ti­ca­tion and de­ploy­ment of container images the systems are secure.

Our com­par­i­son does not include in­de­pen­dent al­ter­na­tives to Ku­ber­netes such as “Apache Mesos” and “Azk”. These are described in our article on Ku­ber­netes al­ter­na­tives. Fur­ther­more, we shall not dive into Ku­ber­netes-as-a-Service (KaaS) offerings from major cloud providers. These can only be used as part of a cloud in­fra­struc­ture of the re­spec­tive provider, for example:

• IONOS Cloud Managed Ku­ber­netes
• Google Ku­ber­netes Engine (GKE)
• Amazon Elastic Ku­ber­netes Service (EKS)
• Azure Ku­ber­netes Service (AKS)
• IBM Cloud Ku­ber­netes Service (IKS)

Ku­ber­netes achieves a pre­vi­ous­ly un­at­tain­able level of au­toma­tion. However, Ku­ber­netes is a highly complex tech­nol­o­gy. Not all or­ga­ni­za­tions have the ex­pe­ri­ence and capacity to run their own Ku­ber­netes in­fra­struc­ture. A “fully-managed” Ku­ber­netes cluster, also known as “Ku­ber­netes-as-a-Service” (KaaS) solves the problem: the provider manages a Ku­ber­netes cluster for the client in the provider’s cloud en­vi­ron­ment. This allows the client to focus entirely on their core business.

A Ku­ber­netes man­age­ment solution is a man­age­ment layer based on Ku­ber­netes. Beyond container or­ches­tra­tion, the complete lifecycle of con­tainer­ized ap­pli­ca­tions can be managed. The Ku­ber­netes clusters used can be hosted on virtually any in­fra­struc­ture, from the public cloud to the company’s own OpenStack en­vi­ron­ment to “bare metal” and edge devices. For the user, this creates func­tion­al­i­ty beyond Ku­ber­netes without tying the system to a specific in­fra­struc­ture provider.

For the purpose of com­par­i­son, we dif­fer­en­ti­ate between fully-managed and self-managed solutions. Some OpenShift al­ter­na­tives are available only as managed solutions. However, all enable operation of work clusters across in­fra­struc­ture bound­aries.

The de­vel­op­ment of Ku­ber­netes man­age­ment solutions is in constant flux. Even though OpenShift al­ter­na­tives have similar functions, they often differ in the details. We summarize the most important features in the table below:

Below you’ll find a brief overview of OpenShift and select leading al­ter­na­tives. In each case, we address the ad­van­tages and dis­ad­van­tages of the al­ter­na­tive, their main dif­fer­ences compared with OpenShift, and common de­ploy­ment scenarios. The following Ku­ber­netes Man­age­ment Solutions are compared:

• Red Hat OpenShift
• SUSE Rancher
• Canonical Ku­ber­netes
• Mirantis Ku­ber­netes Engine (pre­vi­ous­ly Docker En­ter­prise)
• VMware Tanzu (pre­vi­ous­ly Pivotal)
• Platform9 Managed Ku­ber­netes
• Giant Swarm
• Portainer

OpenShift is the fron­trun­ner of Ku­ber­netes Man­age­ment Solutions created by Red Hat. The software is used to build dis­trib­uted, scaling ap­pli­ca­tion and de­vel­op­ment en­vi­ron­ments. Since the early days of Ku­ber­netes, Red Hat has con­tributed con­sid­er­ably to the de­vel­op­ment of the tech­nol­o­gy.

The biggest advantage of OpenShift is the system’s range of functions. In addition to cluster man­age­ment, tech­nolo­gies for the complete man­age­ment of the ap­pli­ca­tion lifecycle are in­te­grat­ed, including de­vel­op­ment, rollout, operation, and main­te­nance. Fur­ther­more, Red Hat provides its own container reg­istries, as well as a catalog of operators.

The large feature set of OpenShift increases the com­plex­i­ty of the software. In­stalling and main­tain­ing OpenShift requires a team of experts, or support as part of a managed solution. To make matters worse, OpenShift’s Ku­ber­netes dis­tri­b­u­tion differs sig­nif­i­cant­ly from the upstream version. Fur­ther­more, OpenShift only runs on Red Hat’s own operating system, Red Hat En­ter­prise Linux CoreOS (RHCOS).

OpenShift is also special in terms of the container images used. Due to the strict security settings, not all images from the freely available repos­i­to­ries can be used. Instead of the Helm charts known from Ku­ber­netes, OpenShift uses pro­pri­etary ap­pli­ca­tion templates to build the in­fra­struc­ture. However, as of the launch of powerful OpenShift operators, an al­ter­na­tive mechanism now exists.

OpenShift is par­tic­u­lar­ly suitable for im­ple­ment­ing hybrid cloud strate­gies and building and scaling the con­tainer­ized ap­pli­ca­tions required. Or­ga­ni­za­tions that are already part of the Red Hat ecosystem will benefit from using the software.

Rancher is a long-standing OpenShift al­ter­na­tive that was acquired by SUSE at the end of 2020. Rancher provides a powerful yet flexible Ku­ber­netes man­age­ment platform. The software fa­cil­i­tates man­age­ment of multiple Ku­ber­netes clusters across different cloud en­vi­ron­ments. Range of functions includes pro­vi­sion­ing, mon­i­tor­ing, and logging.

Besides the oblig­a­tory cluster man­age­ment, Rancher in­te­grates a number of in­ter­est­ing tech­nolo­gies. For example, the “Rancher Ku­ber­netes Engine” (RKE) is a Ku­ber­netes dis­tri­b­u­tion that is published as open source. It offers a minimal K3s dis­tri­b­u­tion for use on edge and IoT devices. This can also be used to implement single node clusters. Rancher features access controls according to the “Open Policy Agency” (OPA) standard and supports the “Longhorn” storage engine.

Rancher is par­tic­u­lar­ly well suited for managing multiple Ku­ber­netes clusters with a cen­tral­ized interface. User rights can be assigned centrally across multiple clusters.

Canonical Ku­ber­netes is another Ku­ber­netes man­age­ment solution from a well-known operating system provider. Ubuntu Linux, developed by Canonical, serves as the foun­da­tion for Ku­ber­netes dis­tri­b­u­tions from major cloud providers such as Google Ku­ber­netes Engine (GKE), Amazon Elastic Ku­ber­netes Service (EKS), and Azure Ku­ber­netes Service (AKS). Thus, with Canonical Ku­ber­netes, users can build clusters that span cloud bound­aries.

The biggest ad­van­tages of Canonical Ku­ber­netes are flex­i­bil­i­ty and low cost of de­ploy­ment. “Charmed Ku­ber­netes” is an exciting operator-based approach to build in­fra­struc­tures. “Charms” is a col­lec­tion to seam­less­ly integrate and manage Ku­ber­netes, container and VM-based ap­pli­ca­tions across hybrid cloud en­vi­ron­ments. Canonical Ku­ber­netes uses Ubuntu as operating system.

Canonical Ku­ber­netes is suitable for a wide range of hardware. Processor ar­chi­tec­tures x86, ARM, IBM POWER, and IBM Z are supported; GPUs can be used in addition to CPU. For use on desktop and edge devices, there is the minimal “MicroK8s” Ku­ber­netes dis­tri­b­u­tion, which is par­tic­u­lar­ly resource-efficient.

Mirantis purchased “Docker En­ter­prise Edition” from Docker Inc. in 2019, and since then the tech­nol­o­gy has been re­launched as “Mirantis Ku­ber­netes Engine”. The software is rooted in the Docker universe. In addition to Ku­ber­netes, Docker Swarm is a supported cluster manager.

The Mirantis Ku­ber­netes Engine occupies an in­ter­est­ing niche. For example, in addition to Linux, it also supports Windows to run on nodes. In­ter­est­ing­ly, Linux and Windows nodes can be mixed seam­less­ly, and the same applies to nodes with Ku­ber­netes or Docker Swarm. The product is aimed at larger busi­ness­es. Thus, it un­for­tu­nate­ly lacks a vibrant community of de­vel­op­ers and the free trial version requires reg­is­tra­tion.

The tech­nol­o­gy is par­tic­u­lar­ly suitable for larger or­ga­ni­za­tions with a strong focus on the developer ex­pe­ri­ence. If an in­fra­struc­ture based on Docker Swarm or Windows nodes already exists, it is rel­a­tive­ly easy to extend it with Ku­ber­netes using the Mirantis Ku­ber­netes Engine.

VMware Tanzu is a Ku­ber­netes platform from vir­tu­al­iza­tion spe­cial­ist VMware. The product resulted from the ac­qui­si­tion of Pivotal by VMware at the end of 2019. With VMware Tanzu, Ku­ber­netes clusters can be built on VMware’s vSphere in­fra­struc­ture. The in­te­grat­ed “Tanzu Mission Control” is a cen­tral­ized interface for managing dis­trib­uted Ku­ber­netes clusters. In addition to func­tion­al­i­ties for de­vel­op­ment and operation of con­tainer­ized ap­pli­ca­tions, mon­i­tor­ing and logging, network and storage man­age­ment are included.

The ad­van­tages of VMware Tanzu are primarily its in­te­grat­ed tools. The “VMware Tanzu Ap­pli­ca­tion Catalog” contains a well-main­tained catalog of open source com­po­nents and ap­pli­ca­tions while “Harbor” is a dedicated container registry to secured different build artifacts by means of role-based access controls. The container images stored in Harbor are checked for security holes and vul­ner­a­bil­i­ties and marked as secure. The focus when using VMware Tanzu is clearly on the de­ploy­ment of vSphere in­fra­struc­ture. Support for other cloud platforms is less so­phis­ti­cat­ed.

VMware Tanzu is par­tic­u­lar­ly suitable for companies that already know their way around the vSphere in­fra­struc­ture. In addition to the com­mer­cial version, a free version is available for Linux, Windows and Mac – the “VMware Tanzu Community Edition”.

Platform9 was founded by former VMware engineers. The core concept of the platform is to run es­tab­lished open-source software like Ku­ber­netes under a software-as-a-service (SaaS) model for customers. This makes it possible to centrally manage Ku­ber­netes clusters dis­trib­uted across different cloud en­vi­ron­ments. Platform9 takes over the main­te­nance of the Ku­ber­netes in­stal­la­tions, which reduces op­er­a­tional com­plex­i­ty on the customer side.

The biggest advantage of Platform9 is its “fully managed” operating model. Clients no longer have to deal with operating system or Ku­ber­netes updates. Other positive features are its clear pricing structure, extensive doc­u­men­ta­tion, and a free trial version. Even though the web interface is a bit outdated, it includes plenty of standard features: the “Prometheus” software con­tin­u­ous­ly checks the health of clusters, and logs are collected and analyzed centrally. Ap­pli­ca­tions available in public Helm repos­i­to­ries can be installed without any problems.

As a special niche, Platform9 focuses on telecom­mu­ni­ca­tion service providers that unite large quan­ti­ties of edge devices in Ku­ber­netes clusters. Fur­ther­more, the platform makes it possible to run “legacy” apps based on virtual machines in parallel to modern, con­tainer­ized ap­pli­ca­tions.

Giant Swarm is a “fully-managed” Ku­ber­netes platform. The software takes over the man­age­ment of the Ku­ber­netes en­vi­ron­ment, ir­re­spec­tive of the type of un­der­ly­ing cloud in­fra­struc­ture used. Clients can thus focus on ap­pli­ca­tions and services run on Ku­ber­netes. The man­age­ment and worker clusters can be operated on Amazon AWS, Microsoft Azure or “on-premises” as part of a client’s existing computing in­fra­struc­ture.

The platform manages and optimizes the entire lifecycle of con­tainer­ized ap­pli­ca­tions and is quickly de­ploy­able. Unlike OpenShift, a Giant Swarm in­stal­la­tion can be set up within a day. Since an un­mod­i­fied Ku­ber­netes dis­tri­b­u­tion is used, it is rel­a­tive­ly easy to move parts of the in­fra­struc­ture between cloud en­vi­ron­ments. This reduces the risk of vendor lock-in. On the negative side, it is no­tice­able that there is no uniform pricing model. Instead, the price is tailored according to the client’s needs.

Giant Swarm is par­tic­u­lar­ly suitable for con­trol­ling dis­trib­uted mi­croser­vice ar­chi­tec­tures. This allows resilient, agile systems to be built and scaled. The software takes over the complex man­age­ment of the un­der­ly­ing in­fra­struc­ture.

Unlike the afore­men­tioned OpenShift al­ter­na­tives, Portainer follows a different concept. It is not a fully-managed platform or Ku­ber­netes dis­tri­b­u­tion of its own. Instead, it uses a graphical user interface that unifies the man­age­ment of existing Ku­ber­netes de­ploy­ments. DevOps teams have the ability to centrally manage, configure, and secure multi-cluster en­vi­ron­ments. At the developer level, de­ploy­ment, man­age­ment, and trou­bleshoot­ing of con­tainer­ized ap­pli­ca­tions is sim­pli­fied.

The main advantage of Portainer is the flex­i­bil­i­ty of the software. In addition to Ku­ber­netes, Docker Swarm and Docker can be used to manage clusters and con­tain­ers. Portainer is based on open-source software and is offered in a freely available community version as well as a paid version with en­ter­prise support. The software can be installed in cloud en­vi­ron­ments, on edge devices, or within a client’s existing computing in­fra­struc­ture. Since Portainer is rel­a­tive­ly new, the doc­u­men­ta­tion leaves much to be desired.

Portainer is par­tic­u­lar­ly suitable for cen­tral­iz­ing and unifying the man­age­ment of existing cluster in­fra­struc­tures. If Docker or Docker Swarm-based systems are used in addition to Ku­ber­netes, they can be managed with ease.