Azure calls its equivalent of AWS Spot instances “low priority.” When I checked, a low-priority D32-v3 instance in the Eastern zone cost $0.345 per hour, versus $1.60 per hour on demand. I wasn’t able to select this option in my account, however.
|Azure D32-v3 instance||Cost||Savings|
Google’s equivalent of Spot instances are called “preemptible instances.” A preemptible VM is an instance that you can create and run at a much lower price than normal instances. However, Compute Engine might terminate (preempt) these instances if it requires access to those resources for other tasks. Preemptible instances are excess Compute Engine capacity so their availability varies with usage. A preemptible n1-standard-32 instance in the Northern Virginia zone currently costs $0.3424 per hour, versus the full price of $1.712 per hour and the sustained use price of $1.52 per hour. According to Google, the preemption rate typically varies in the range of 5% to 15% per seven days per project.
|Google Cloud n1-standard-32||Cost||Savings|
Underutilized servers and limited space for new racks led enterprises to turn some dedicated servers in their data centers into hosts for VMs. Then, when memory utilization in VM hosts became an issue, they turned some of their VMs into hosts for containers.
The basic difference between virtualizing with VMs and virtualizing with containers is that, in addition to the application software, a VM contains a full operating system and a full set of virtualized hardware, while a container contains only parts of an operating system, some libraries, and the application software. Both VMs and containers offer some isolation from other applications; VMs offer more isolation and better security, albeit at a high cost in memory usage.
RAM is one of the most expensive resources to lease in the cloud, and containers typically need only one-third of the RAM to run the same software as a VM. This makes running your cloud estate in containers an attractive cost proposition, as long as the reduced isolation isn’t a problem.
Up until fairly recently, container use has been limited to Linux-based systems, and orchestration, tool support, and instrumentation for containers were lacking. None of that is really a problem anymore, and moving your loads to containers in the cloud is a good way to streamline your operations and reduce your cloud expenditure.
At AWS, there is no extra charge for running containers — you only pay for the underlying VMs and storage. Azure lets you create and use containers directly from a pool, and charges $0.0025 per Instance created, plus $0.0000125 per GB-second and $0.0000125 per core-second. For example, if you run three containers simultaneously for a month, and each container uses 1GB of memory and 2 cores, you’ll pay less than $300 per month for them.
|Azure container||Instance cost||Cost per GB-second||Cost per core-second||Duration||Total|
|1GB, 2 cores||$0.0025||1 x $0.0000125||2 x $0.0000125||30 days||$97.20|
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