Difference between containers and virtual machines
Both Containers and Virtual Machines are known as virtualization technologies that allow applications to be deployed in a virtual environment isolated from the underlying hardware, which is why they look so similar. But, in terms of specific uses, they differ from each other. In this article, I will introduce the difference between containers and virtual machines, which aims to help you decide which tool you should use in your environment.
What’s the difference between container and VM
First, you need to know the basic meaning in order to have a deeper understanding between VM and container, such as docker container.
Virtual machine is a technology used to virtualize computing environments which emulates of the underlying hardware such as CPUs, disks, network devices and etc. to virtualize a physical computer (server), so you can perform multiple operating systems based on a single computer. The complete OS makes the virtual machine height weight (often up to several gigabytes in size), which takes several minutes to boot it.
Generally, virtual machine needs to interact with the physical computer through the hypervisor which separates the VM and physical host and assign the hardware resource to virtual machines.
Container creates an isolated environment in a physical host (server) by sharing the host operating system and executing the packaged applications. Container sits on top of the physical server and host OS, and each container can share the host OS Kernel as well as binaries and libraries, which is more lightweight (only a few MB in size) and takes a few seconds to boot.
Containers VS Virtual Machines: Pros and Cons
After the basic introduction of container and VM, you need to understand the difference of advantages and disadvantages between virtual machine and container, so you can choose a more suitable tool to carry out your workload.
Pros of virtual machine:
1. Security: Each virtual machine has a completely independent operating system and won’t be affected by other attacked or hijacked VMs on the shared host.
2. Run multiple operating systems: You can install various operating system on virtual machines when testing applications, which eliminates the additional cost of hardware.
3. Better allocation of resources: If you want to perform resource-intensive tasks, virtual machine is an ideal choice because it can allocate resources properly according to your needs.
Cons of virtual machine:
1. Expensive storage costs: Virtual machines initially take up less storage space, but they can quickly grow to several gigabytes or even tens of gigabytes over time, which can lead to a lack of disk space on the physical host. Therefore, running multiple VMs requires a hard drive with a large enough capacity.
2. Slow iteration: Since the virtual machine contains a complete stack system, it can take a lot of time to rebuild it. In addition, when you make changes to snapshots, it also requires large amounts of time to rebuild and verify the changed settings.
3. Updating and maintenance: Since virtual machines are independent and there are multiple operating systems on a server. When you need to update or maintain an OS, you need to do so on a case-by-case basis.
Pros of container:
1. Portability: Since containers are packaged together with microservices and all their dependencies, you can easily move containers across different environments such as to bare metal VM, public cloud, private cloud, etc.
2. Performance: Since the container is lightweight and shares the host operating system, it’s faster to boot a container than virtual machine, and it saves time costs for maintenance and updates.
3. More efficient use of resources. Code packaged in containers can be shared to execute most of dependencies, including operating systems, libraries, frameworks, etc. This also means that more containers can be accommodated in the same physical server.
Cons of container:
1. Insecurity: Containers are different for virtual machines, and they share the same underlying hardware of the OS. If a vulnerability occurs in one of the containers, it is likely to affect the other containers directly with the shared hardware, especially the pre-built public repository within the container, which can easily become a source of security risk.
2. Single system: All containers must run on a shared operating system, which means you can't run multiple operating systems at the same time when you want to test the certain function of applications in different environments.
Should you use container or virtual machine
For containers cases, if you want to work witth a minimal number of servers, build cloud-native applications or need to move your project across different environments, container is the best choice for you.
On the other hand, if you need to run different operating systems and need a secure platform to store your data for a long-term, virtual machine is more suitable in your production environment. With virtual machine backup, it safeguards your business data continuously.
The detailed differences between virtual machine and container.
Containers VS Virtual Machines: Major software
For virtual machine, VMware, Virtualbox, QEMU are all famous virtual machine programs.
VMware is one of the most recognizable cloud computing and virtualization technology companies with a history dating back to x86 hardware virtualization technology, and much of VMware's popularity relies on a powerful hypervisor that allows you to deploy and manage as many virtual machines as you need.
Virtualbox is Oracle's free, open-source emulation with x86 architecture and one of the most popular virtual machine platforms available today, providing hardware-assisted virtualization, which will help develop and distribute virtual machine images.
QEMU is a free open-source software for creating emulation and virtual machine environments and supports the common hardware architecture. QEMU can also do emulation for user-level processes, allowing applications compiled for one architecture to run on another.
For container, you may be familiar with Docker, RKT and Linux Containers (LXC).
Docker is a set of platform as a service products that use OS-level virtualization and enables developers to easily pack, ship, and run any application.
RKT, also known as Rocket, is a security-centric container that strictly prohibits the risky features and focus on potential cross-contamination issues when other containers are running.
Linux Containers is actually an open-source Linux container system that can effectively isolate processes at the operating system level.
Data protection tool for virtual machines – AOMEI Cyber Backup
AOEMI Cyber Backup is a professional tool to backup and protect virtual machines in your production environment. It automates the backup of unlimited virtual machines in business and offers flexible strategies to prevent data-loss due to the natural disaster, power outage, human errors, etc.
Full compatibility: It supports VMs on VMware ESXi 6.0 and later versions, as well as Hyper-V in Windows 8/8.1/10/11, Windows Server/Microsoft Hyper-V Server 2012 R2 and later versions.
Offsite Restore: It is capable of restoring the VM backup to new datastore or host easily without any complicated installation or configuration.
Automatically protect VM: It can schedule hot backups for virtual machines and offer comprehensive backup strategies to regularly protect data.
Affordable VM protection: With one license, you can back up multiple virtual machines on the host, and restore it within a few clicks.
1. Download AOMEI Cyber Backup and add VMware ESXi host as an example.
2. Click Backup Task >> Create New task.
- Device: select one or more virtual machines for backup.
- Target: select a local or network location to store backup files. You can easily backup all the virtual machines to NAS or to external hard drive.
- Schedule: set up the automated backup task with full, differential or incremental backup and specify the time as daily, weekly or monthly.
- Cleanup: specify a retention period. If the old backup files exceed the period, they will be automatically deleted.
After that, you can click Start Backup and select to Add the schedule and start backup now, or Add the schedule only.
3. Restore: click Restore and choose the restore content and target. You can restore the VM to another host easily without any complicated reinstallation or configuration.
This article explains the differences between containers and virtual machines including the basic introduction, advantages and disadvantages, and the main softwares. I hope this article can help you choose a more appropriate virtualization technology.
However, it is important to note that virtual machines and containers are not completely opposed to each other, and you can use both tools to take advantage of their complementary strengths.