Resizing a virtual machine using 3Engines Horizon on 3Engines Cloud[πŸ”—](#resizing-a-virtual-machine-using-3Engines-horizon-on-brand-name "Permalink to this headline") ========================================================================================================================================================================= Introduction[πŸ”—](#introduction "Permalink to this headline") ----------------------------------------------------------- When creating a new virtual machine under 3Engines, one of the options you choose is the *flavor*. A flavor is a predefined combination of CPU, memory and disk size and there usually is a number of such flavors for you to choose from. After the instance is spawned, it is possible to change one flavor for another, and that process is called *resizing*. You might want to resize an already existing VM in order to: > * increase (or decrease) the number of CPUs used, > * use more RAM to prevent crashes or enable swapping, > * add larger storage to avoid running out of disk space, > * seamlessly transition from testing to production environment, > * change application workload byt scaling the VM up or down. In this article, we are going to resize VMs using commands in 3Engines Horizon. Prerequisites[πŸ”—](#prerequisites "Permalink to this headline") ------------------------------------------------------------- No. 1 **Account** You need a 3Engines Cloud hosting account with access to the Horizon interface: . No. 2 **How to create a new VM** If you are a normal user of 3Engines Cloud hosting, you will have all prerogatives needed to resize the VM. Make sure that the VM you are about to resize belongs to a project you have access to. Here are the basics of creating a Linux VM in Horizon: [How to create a Linux VM and access it from Linux command line on 3Engines Cloud](How-to-create-a-Linux-VM-and-access-it-from-Linux-command-line-on-3Engines-Cloud.html.md) [How to create a Linux VM and access it from Windows desktop on 3Engines Cloud](How-to-create-a-Linux-VM-and-access-it-from-Windows-desktop-on-3Engines-Cloud.html.md) No. 3 **Awareness of existing quotas and flavors limits** For general introduction to quotas and flavors, see [Dashboard Overview – Project Quotas And Flavors Limits on 3Engines Cloud](Dashboard-Overview-Project-Quotas-And-Flavors-Limits-on-3Engines-Cloud.html.md). Also: > * The VM you want to resize is in an active or shut down state. > * A flavor with the desired resource configuration exists. > * Adequate resources are available in your 3Engines environment to accommodate the resize. Creating a new VM[πŸ”—](#creating-a-new-vm "Permalink to this headline") --------------------------------------------------------------------- To illustrate the commands in this article, let us create a new VM in order to start with a clean slate. (It goes without saying that you can practice with any of the already existing VMs in your account.) Use Prerequisite No. 2 to create a new VM and let it be called **Resizing**. Here is a typical list of flavors you might see: ![resize-vm-horizon-1.png](../_images/resize-vm-horizon-1.png) For the sake of this article, let us choose a β€œmiddle” flavor – not too large and not to small to start with. Let it be **eo2a.large**. ![resize-vm-horizon-2.png](../_images/resize-vm-horizon-2.png) Finish the process of creating a new VM and let it spawn: ![resize-vm-horizon-3.png](../_images/resize-vm-horizon-3.png) Let us now resize the VM called **Resizing**. Steps to Resize the VM[πŸ”—](#steps-to-resize-the-vm "Permalink to this headline") ------------------------------------------------------------------------------- Locate the VM by using Horizon commands **Compute** -> **Instances**. Click the dropdown arrow next to the VM and select **Resize Instance**. ![resize-vm-horizon-4.png](../_images/resize-vm-horizon-4.png) You get form **Resize Instance** on screen: ![resize-vm-horizon-5.png](../_images/resize-vm-horizon-5.png) Assuming you wanted to scale up the VM, you could decide upon **eo2.xlarge**. Let us compare the two flavors: | Flavor | VCPUs | RAM | Total Disk | Root Disk | | --- | --- | --- | --- | --- | | eo2a.large | 2 | 7.45 GB | 32 GB | 32 GB | | eo2.xlarge | 4 | 16 GB | 64 GB | 64 GB | So, select **eo2.xlarge** as the new flavor. This screen shows its parameters: ![fwaas-openvpn-v2-34.png](../_images/fwaas-openvpn-v2-34.png) Advanced Options[πŸ”—](#advanced-options "Permalink to this headline") ------------------------------------------------------------------- **Advanced Options** tab contains two further options for resizing the instance. ![resize-vm-horizon-10.png](../_images/resize-vm-horizon-10.png) Disk Partition : Whether the entire disc is a single partition and automatically resizes. Options are **Automatic** and **Manual** Server Group : Here you select server group to which the instance can belong after resizing. Even if you never manually created a server group, they may be present as a consequence of creating Kubernete clusters, or using parameters for group affinity. The list can be quite long: ![resize-vm-horizon-11.png](../_images/resize-vm-horizon-11.png) Resize the VM[πŸ”—](#resize-the-vm "Permalink to this headline") ------------------------------------------------------------- Anyways, click on **Resize** to proceed with the resizing of the VM. ![resize-vm-horizon-8.png](../_images/resize-vm-horizon-8.png) In **Status** column, there will be message **Confirm or Revert Resize/Migrate**. It means the system is waiting for you to decide what to do next. To confirm the resizing/migrating process, click on button **Confirm Resize/Migrate** in the **Actions** column. The resizing process will finish within a couple of seconds and the VM will be in **Status** Active. If you encounter issues, you can choose **Revert Resize** to return the VM to its previous state. This option is, however, only available before **Resize/Migration Confirmation**. Or, if the resizing is finished, you can again use option **Resize instance** and choose the flavor from which you started (**eo2a.large** in this case). This process of scaling down is much faster than the process of scaling up. Troubleshooting[πŸ”—](#troubleshooting "Permalink to this headline") ----------------------------------------------------------------- If any of the flavor parameters does not match up, the resizing will fail. You will then see balloon help in the right upper corner: ![resize-vm-horizon-7.png](../_images/resize-vm-horizon-7.png) In this case, the sizes of the disk before and after the resizing do not match. What To Do Next[πŸ”—](#what-to-do-next "Permalink to this headline") ----------------------------------------------------------------- You can also resize the virtual machine using only 3Engines CLI. More details here: [Resizing a virtual machine using 3Engines CLI on 3Engines Cloud](../3Enginescli/Resizing-a-virtual-machine-using-3Engines-CLI-on-3Engines-Cloud.html.md)