142 lines
5.3 KiB
Markdown
142 lines
5.3 KiB
Markdown
Resizing a virtual machine using OpenStack CLI on 3Engines Cloud[🔗](#resizing-a-virtual-machine-using-openstack-cli-on-brand-name "Permalink to this headline")
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=================================================================================================================================================================
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Introduction[🔗](#introduction "Permalink to this headline")
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-----------------------------------------------------------
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When creating a new virtual machine under OpenStack, 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.
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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:
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> * increase (or decrease) the number of CPUs used,
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> * use more RAM to prevent crashes or enable swapping,
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> * add larger storage to avoid running out of disk space,
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> * seamlessly transition from testing to production environment,
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> * change application workload byt scaling the VM up or down.
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In this article, we are going to resize VMs using CLI commands in OpenStack.
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Prerequisites[🔗](#prerequisites "Permalink to this headline")
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-------------------------------------------------------------
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No. 1 **Account**
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You need a 3Engines Cloud hosting account with access to the Horizon interface: <https://portal.3Engines.com/>.
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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.
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[How to create a VM using the OpenStack CLI client on 3Engines Cloud cloud](../cloud/How-to-create-a-VM-using-the-OpenStack-CLI-client-on-3Engines-Cloud-cloud.html.md)
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No. 2 **Awareness of existing quotas and flavors limits**
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For general introduction to quotas and flavors, see [Dashboard Overview – Project Quotas And Flavors Limits on 3Engines Cloud](../cloud/Dashboard-Overview-Project-Quotas-And-Flavors-Limits-on-3Engines-Cloud.html.md).
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Also:
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> * The VM you want to resize is in an active or shut down state.
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> * A flavor with the desired resource configuration exists.
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> * Adequate resources are available in your OpenStack environment to accommodate the resize.
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Creating a new VM[🔗](#creating-a-new-vm "Permalink to this headline")
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---------------------------------------------------------------------
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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.)
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To see all flavors:
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```
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openstack flavor list
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```
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This is the command to create a new VM called **ResizingCLI**:
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```
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openstack server create \
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--image "Ubuntu 22.04 LTS" \
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--flavor eo2a.large \
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--key-name sshkey \
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--network cloud_00341_3 \
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--security-group default \
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--security-group allow_ping_ssh_icmp_rdp \
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ResizingCLI
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```
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This is the result:
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The **id** for **ResizingCLI** is **82bba971-8ff1-4f85-93d6-9d56bb7b185d** and we can use it in various commands to denote this particular VM.
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To see all currently available VMs, use command
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```
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openstack server list
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```
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Steps to Resize the VM[🔗](#steps-to-resize-the-vm "Permalink to this headline")
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-------------------------------------------------------------------------------
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To resize a VM with CLI, there is a general command
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```
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openstack server resize --flavor <new_flavor> <vm_name_or_id>
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```
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We need flavor ID or name as well as VM’s name or id.
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In this example we want to scale up the existing VM **ResizingCLI**, using **eo2.xlarge** flavor. The command will be:
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```
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openstack server resize --flavor eo2.xlarge ResizingCLI
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```
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To verify the resize, check the status of the VM:
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```
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openstack server show ResizingCLI
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```
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When the VM has **VERIFY\_RESIZE** status, we are able to confirm the resize. The command is:
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```
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openstack server resize confirm ResizingCLI
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```
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Execute once again:
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```
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openstack server show ResizingCLI
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```
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to see the real state of the VM after confirmation. We will now see that the **status** is **ACTIVE**.
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Reverting a resize[🔗](#reverting-a-resize "Permalink to this headline")
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-----------------------------------------------------------------------
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Reverting a resize switches the VM back to its original flavor and cleans up temporary resources allocated during the resize operation.
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It is only possible to revert a resize if the status is **VERIFY\_RESIZE**. The command would be:
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```
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openstack server resize revert ResizingCLI
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```
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If status is not **VERIFY\_RESIZE**, we will get message stating that it is not possible to revert resize while it is in an active state (HTTP 409). In that case, perform the “regular” resizing with **openstack server resize**.
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What To Do Next[🔗](#what-to-do-next "Permalink to this headline")
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-----------------------------------------------------------------
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You can also resize the virtual machine using only OpenStack CLI. More details here: /openstackcli/Resizing-a-virtual-machine-using-OpenStack-Horizon-on-3Engines-Cloud |