Thursday, October 25, 2018

#663 OCI - Compute Service in some more detail

Create Compute Instance

Please note: All text in italics is from the Oracle docs

Check out the shape types above  - Virtual Machine or Bare Metal

Bare Metal

A bare metal compute instance gives you dedicated physical server access for highest performance and strong isolation.

Essentially a single-tenant model - no noisy neighbours. You also get direct hardware access.
So who should go for this? For example, customers with performance intensive requirements.

Virtual Machine

A Virtual Machine (VM) is an independent computing environment that runs on top of physical bare metal hardware. The virtualization makes it possible to run multiple VMs that are isolated from each other. VMs are ideal for running applications that do not require the performance and resources (CPU, memory, network bandwidth, storage) of an entire physical machine.

Details of the available shapes for both options are here

Bare Metal includes GPU based shapes, optimal for high performance and machine learning.

The VM shapes support the following operating systems -

BYOI is also supported for older versions of a particular O/S etc.

Here I am creating an Oracle Linux based VM -

Boot Volumes

When you launch a virtual machine (VM) or bare metal instance based on an Oracle-provided image or custom image, a new boot volume for the instance is created in the same compartment. That boot volume is associated with that instance until you terminate the instance. When you terminate the instance, you can preserve the boot volume and its data.

All boot volumes are encrypted and ensure faster boot times and enable compute instance scaling.
You can create a custom image based on a boot volume and then select that when creating a new instance. Backups/cloning is also supported.

Block Volumes

The Oracle Cloud Infrastructure Block Volume service lets you dynamically provision and manage  block storage volumes . You can create, attach, connect and move volumes as needed to meet your storage and application requirements. Once attached and connected to an instance, you can use a volume like a regular hard drive. Volumes can also be disconnected and attached to another instance without the loss of data.

Regarding the Backup Policy -
gold - daily
silver - weekly
bronze - monthly

Now I can attach it to my compute instance -

iSCSI: A TCP/IP-based standard used for communication between a volume and attached instance.
Paravirtualized: A virtualized attachment available for VMs.

The iSCSI commands are available here -

I ssh into the vm and execute the register cmd -

Note the positive response above.

I now execute the cmd to automatically re-connect after reboot -

I do sudo su - and login to iSCSI -

fdisk -l

note the root volume sda and the new volume sdb

I format it -mkfs.ext3

and then mount it - mount /dev/sdb /mnt/hotd

Edit /etc/fstab to mount automatically -

Firstly, I need the UUID for sdb - blkid

Format of entry in fstab is as follows -
UUID=699a776a-3d8d-4c88-8f46-209101f318b6 /mnt/vol1 xfs defaults,_netdev,nofail 0 2
In my case -

File Systems

Oracle Cloud Infrastructure File Storage service provides a durable, scalable, distributed, enterprise-grade network file system. You can connect to a File Storage service file system from any bare metal, virtual machine, or container instance in your Virtual Cloud Network (VCN). You can also access a file system from outside the VCN using Oracle Cloud Infrastructure FastConnect and Internet Protocol security (IPSec) virtual private network (VPN).

Now to mounting the file system I just created - again, all I need to do is to copy and paste the commands -

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