Understanding of Compute Instances \ Virtual Machine in GCP

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Understanding of Compute Instances in GCP
Compute Instance or Virtual Machine in GCP
A virtual machine is a separate machine created over the physical one with some resources from the physical machine. A virtual machine can have separate OS, network than the physical host. We will be discussed about Virtual Machine Instances hosted on a Google Cloud Platform, also known as Compute Instances. In GCP, all VM created with the UTC timezone regardless of your or selected region time zone.
Key factors of Compute instance
OS Images: Compute instances in GCP can be created using public images of Linux or Windows that Google provided, or customized or private images created by you or imported from other sources. Customized & Private images need additional configuration and ay lead to additional cost.
Projects: Each resource in the Google Cloud Platform belongs to Project. When you create VM in the project, you mentioned zone, storage, operating system, and machine type. Based on the billing account associated with projects, VM is charged.
Storage: In GCP, each virtual machine has a small boot persistent disk used to keep the operating system. This disk created at the time of compute instance creation and machine used this for a start-up. You can further add storage for application or database files. GCP provided multiple types of storage and you review & chose an appropriate one.
Network: Each computes instance or VM is connected to at least one VPC network.
Compute instance can continue using a physical box network or have a separate network.
Access: You can access your instance in multiple ways based on OS. For Linux, you can create SSH key or OS user credentials and for windows, you can create AD login or OS user credentials.
GPU support: Compute Instance provided GPU (Graphical Processing Unit) support and you can add GPU resources to your instance. In case you are using 3D rendering or virtualization, you can leverage it to explore it. The availability of GPU resources and versions are subjected to availability with the region. You can explore the list if GOC resources available with different regions.
Machine Type: Machine type is a set of hardware for VM instance. The selection of appropriate machine type is required for the well functioning of your application or process with efficient budget control. Compute instance consist of vCPU, Memory, Network, Disk, Persistent Disk, GPU Support, etc.. You need to select machine type at the time of VM creation. In GCP, you can change the machine type whenever required subject to availability in the required region. In GCP, Google provides you 4 types of machines.
Instance Life Cycle
A VM or compute instance can transition through multiple stages as part of the instance life cycle.
PROVISIONING: State, when you create an instance and allocated resources however instance, is not running yet.
STAGING: Resources allocated to instance have been acquired and the instance is ready for first boot.
RUNNING: State when the instance is booting up & running. You can do SSH or use server credentials to connect instance. This is the stage where you are charged for running VM as well as the attached resources. An instance can move to 3 stages from Running:-
STOPPING Terminated
Suspending Suspended
Resetting: Resetting is a clean-up process more than the stage. In resetting, wipe the memory contents of the VM instance and reset the virtual machine to its initial state. Resetting issue hard restart and does not do graceful shutdown although maintain persistent disk data.
STOPPING: Here, the instance is stopped on the user requested or due to some failure. You can keep an instance in this stage to preserver OS configuration and application files. You will not be charged for running VM however cost of attached resources like disk will occur. This is a temporary status and the instance will move to the TERMINATED stage.
TERMINATED: The instance is shutdown by the user or due to some failure. You can choose to restart or delete instances from here. As mentioned before, you will not be charged for running VM however cost of attached resources like disk will occur.
SUSPENDING: User issued suspend action on the instance and instance in process.
SUSPENDED: When the instance is suspended, you can choose to resume or delete instances from here. You can choose this state when you want to save the live state of instance and no concern over cost. In the Suspended stage, you will be charged similar to running VM because instance will be kept running in the background to maintain the live state on the instance.