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In some cases, public cloud services don't offer admins full visibility and control, particularly around variable workload performance and security. Some providers address this challenge by offering bare-metal cloud.
What are bare-metal cloud services?
A bare-metal cloud service is a variation on infrastructure as a service (Iaas) that allows users to rent and configure single-tenant servers, typically without a virtualization layer. Bare-metal cloud promises the flexibility and scalability of public cloud, with the predictability, granularity and security of local servers.
Not all workloads run well on the virtualized cloud instances that make up many IaaS offerings. For example, legacy applications that demand access to physical hardware, or workloads that are extremely stable and require no scalability, might be better fits for bare-metal cloud.
Bare-metal cloud services are similar to other cloud services -- they're accessible like Amazon Web Services (AWS) Elastic Compute Cloud (EC2) instance or an Azure D-series VM. The primary difference with bare-metal is that the service maps to a physical server rather than a VM. Since the server is rarely virtualized, users get complete access to the entire server directly and all of its compute, storage and network resources. A bare-metal cloud instance is almost indistinguishable from a more traditional server, but typically uses the same on-demand rental model that public cloud providers use.
There are numerous providers in the bare-metal cloud market, including Oracle, IBM, baremetalcloud, Rackspace and Internap.
Major public cloud providers, including Azure and Google, do not have strong bare-metal cloud offerings. AWS comes close with its Dedicated EC2 Hosts service, which commits an entire physical server to the user.
What are the pros and cons of bare-metal cloud services?
The most notable benefit of bare-metal cloud services is direct control of the server and its resources. This is a far cry from typical virtualized cloud instances, which intentionally obscure underlying hardware operations from the users. Additionally, without the virtualization layer, bare-metal cloud reduces the overhead of a hypervisor, which can increase performance.
Because most public IaaS environments are multi-tenant, organizations are concerned with security and compliance. Bare-metal cloud instances address both of these concerns because they provide a single-tenant hardware platform committed exclusively to a single user. However, bare-metal clouds do not guarantee security or compliance; organizations need to understand the legal obligations and industry best practices for proper security and regulatory posture.
Bare-metal cloud instances can also be more cost-effective than public cloud instances because users generally pay only for the underlying hardware rather than usage. However, organizations must consider the costs and compare to in-house hardware acquisition, deployment and operational expenses.
However, compared to virtualized instances, bare-metal cloud services can be limited. For example, when a physical server is virtualized, admins can provision a wide range of standardized VM types from the underlying hardware. But a bare-metal cloud instance is a complete server, so there is a limited number of instance sizes and types available.
What makes bare-metal cloud management unique?
There are few fundamental differences in managing bare-metal cloud instances versus typical virtual machine public cloud instances.
For example, bare-metal cloud providers like Rackspace and Oracle provide management interfaces, including a console and command-line interface. The Rackspace control panel offers a web-based interface to start the cloud server, access and view KPIs, schedule tasks like snapshots and access support functions. Admins can use control panels to perform tasks such as server resets and power cycling -- tasks unthinkable with common VM instances.
However, bare-metal servers generally require a more granular level of management and control than common cloud instances. For example, Oracle organizes bare-metal cloud services into entities called compartments, which provide isolated cloud instances to other business units or projects. This means it is possible to monitor, manage and track billing for resources by activity or group, and assign granular security and data protection characteristics to each individual user. Admins familiar with managing VM-based public cloud instances may see an additional learning to set up and manage a bare-metal cloud environment.
Is bare-metal cloud a better option for higher-level services?
Bare-metal cloud services can be a good option when a workload's computing demands are relatively constant due to lack of scalability. Workloads that fit this model include those involved with big data analytics, backup and recovery cycles, media encoding tasks, machine learning, visual rendering projects and other I/O-intensive applications.
For example, a big data workload needs to ingest a large amount of data, transform and process that data and then pass results back to storage. Once completed, the server may remain unused for weeks or even months. This makes bare-metal cloud a viable option, rather than buying and owning servers permanently.
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