Compute from the exam (OCI) point of view contains 15% of the total exam weighage. The Compute Module contains important topics such as Compute type (Bare Metal & Virtual Machine), Shape (Standard, HighIO, DenseIO, GPU), Compute Images, and Boot Volumes
This post covers the Q/A & Review from Day 4 of Oracle Cloud Infrastructure Architect Associate Training Program covering Compute (Type- BM & VM, Shape, Service Images, Boot Volume, Instance Creation)
- For Q/A & Review from Day 3, covering Networking (VCN, Subnets, Gateways, Route Tables, Security List), please check Here.
- For Q/A & Review from Day 2, covering IAM (Compartments, Policies, Users, Groups) please check Here.
- For Q/A & Review from Day 1, covering Region, AD & FD, OCI Services please check Here.
In this session, we covered Module 4: OCI Compute which includes the following lessons:
The Training Program available on the Membership Portal looks like the screenshot below. We encourage the trainees to go through the well-done recorded videos before attending the Live session so they can come up with their doubts & clear them during the session to make it more Interactive.
[Q/A] Compute (BM & VM)
We started this Module with Compute Types (BM & VM).
Bare Metal: A Bare Metal Compute Instance gives you dedicated physical server access for the highest performance and strong isolation. It is a Non-Shared Hardware, ideal for the customers with a strict regulatory requirement whereby sharing at VM level is not permitted.
Virtual Machine: A virtual machine (VM) is an independent computing environment that runs on the top of a hypervisor. The virtualization makes it possible to run multiple VMs that are isolated from each other.
Here are some questions related to Compute Types discussed during the session:
Q1. For OCI, on which hypervisor all the Oracle provided VMs are based?
Ans: For OCI, the hypervisor is KVM based whereas for OCI – C, the hypervisor is Xen based.
- To know more about OCI vs OCI – C, please check Here.
Q2. Is KVM actually the operating system which has the hypervisor inbuilt in the kernel?
Ans: The KVM hypervisor is a type 1 hypervisor that comes with the kernel. It is installed on top of a BM and top of that applications are run in the VM, so no operating system is required in case of a KVM.
- To know more about KVM, please check Here.
Q3. How come BM billing will stop on stop state?
Ans: There are different types of shapes:
- Standard (BM & VM)
- High I/O Bare metal
- Dense I/O (BM & VM)
- GPU (BM & VM)
— For Standard VM and Bare Metal instances, billing pauses on the stop state.
— For HPC, High I/O Bare Metal, Dense I/O Bare Metal and VM instances, billing continues until the Instance is terminated
[Q/A] Compute Images
Next, we discussed the Compute Images, and here is a high-level overview of the same.
Images are used to launch Instances (Compute) in OCI. You specify which image to use when launching an instance and it is the image that determines the operating system and other software for an Instance. Images that can be used to launch new instances are of the following types:
- Platform Images: Pre-built images for OCI.
- Oracle Images: Pre-built enterprise solution running on OCI from Oracle (EBS, JDE, etc).
- Partner Images: Trusted third-party images published by Oracle partners.
- Custom Images: Created or Imported into OCI by You (like from VMDK).
- Boot Volumes: Boot Volumes for creating a new Instance.
- Image OCID
Here are some questions related to Compute Images:
Q3. Can we install our own OS or we need to use only the images from Oracle?
Ans: You can install any OS of your choice including BYOL as long as it is compatible with the Oracle Cloud Hardware. There should be a certification matrixes for supported OS.
- You can import images in either QCOW2 or VMDK formats.
Q4. What is OCPU Exactly?
Ans: Oracle’s definition of CPU. Oracle calculates license based on OCPU. An OCPU is defined as the CPU capacity equivalent of one physical core of an Intel Xeon processor with hyperthreading enabled. For the Intel Xeon processor, each OCPU corresponds to two hardware execution threads known as vCPUs.
[Q/A] Boot & Block Volumes
Here, we give an overview of Boot & Block Volumes along with how they play a major role in Storage:
Note: Volumes will be covered in the next session i.e. Storage
Boot Volume: When you launch a virtual machine (VM) or bare metal Instance based on an Oracle-provided image custom image, a new boot volume for the Instance is created automatically in the same compartment. Boot volume is associated with that instance until you terminate the Instance and even when you terminate the Instance, you can still preserve the boot volume and its data.
- Boot volume can be detached (only from stopped Instance) and attached as block volume to another Instance for troubleshooting.
- You can clone a boot volume and use it to launch a compute Instance
Block Volume: The Oracle Cloud Infrastructure Block Volume service lets you dynamically provision and manage block storage volumes. You can create, attach, connect, and move volumes needed to meet your storage and application requirements.
Here are some Q/A related to Boot & Block Volumes:
Q5. What is the Boot Volume used for and how is it different from a custom image?
Ans: Boot volume is the disk that holds OS files and packages required to make the Instance up and running. You cannot make the Instance up without boot volume and by default, it is created with any Instance you provision.
You can create a custom image of a bare metal Instance’s boot disk and use it to launch other Instances. The custom image consists of the Boot volume only associated with the Instance and no other data volume will be included in a custom image. Instances you launch from your image include the customizations, configuration, and software installed when you created the image.
Note: Our Step-By-Step Hands-On Guide covers creating Instances from Custom Images and Boot Volumes, in our Oracle Cloud Infrastructure Architect Training Program
Q6. What is the Bucket in OCI?
Ans: The Bucket is an area in Object Storage to store data. We will cover the Bucket in detail in our Storage module i.e. Module 5 of Oracle Cloud Infrastructure Architect Training Program.
Q7. Do you have exercises on creating images out of Boot Volume and make own image (custom image)?
Ans: Under Module 4 AG, we have the Steps for how to create a Custom Image & how to use it during the Instance creation.
After creating the backup for the boot volume, we can create the required custom image from the same boot volume.
For the Step-By-Step Hands-on Activity Guide, please check Here.
[Q/A] Cloud-Init & Metadata
Cloud-Init & Metadata are crucial for performing checks and making things easier, such as for Instance initialization in case of Cloud-Init script and checking metadata information in case of metadata respectively.
Q8. What is Cloud-init Script?
Ans: Cloud-init is a way to run additional scripts with Instance initialization for hostname, package name, when an instance is created it is going to execute the script at the time of creation and install those packages.
Cloud-init makes it easier and faster to customize your VM – install users, configure ssh keys, install packages, run commands at boot, etc. It is particularly useful when you aim to install a lot of identical machines or very similar machines with the same installations and configurations, or only one machine that has a lot of complex configuration details.
Q9. How can we get Metadata info?
Ans: The metadata for an instance includes its OCID, display name, compartment, shape, region, availability domain, creation date, state, image, and any custom metadata that you provide, such as an SSH public key.
You can find some of this information in the Console on the Compute page, or you can get all of it by logging in to the instance and using the metadata service. The service runs on every instance and is an HTTP endpoint listening on 169.254.169.254.
NOTE: For windows details, the same command we run it in the browser to get the details.
- [Q/A] Oracle Cloud Infrastructure Architect Certification Training Program Day 1 Review: Region, AD & FD, OCI Services
- [Q/A] Oracle Cloud Infrastructure Architect Certification Training Program Day 2 Review: IAM (Compartments, Policies, Users, Group
- [Q/A] Oracle Cloud Infrastructure Architect Certification Training Program Day 3 Review: Networking (VCN, Subnets, Gateways, Route Tables, Security List)
- Oracle Cloud Infrastructure (OCI) Architect Live Training Program.
Next Task For You
- Download the Step-By-Step Activity Guide to Register for an Oracle Cloud Trial Account.
- Create Compute Instances in Oracle Cloud, to know more about how to create a Compute, please check Here.
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