AWS - EC2

由 datahunter 在六, 17/10/2020 - 01:27 發表

最後更新: 2022-05-05

Instance

AMI PV vs HVM

PV: Paravirtual
HVM: Hardware Virtual Machine

Paravirtual guests can run on host hardware that does not have explicit support for virtualization.
(Intel Virtualization Technology)

Boot

PV AMIs boot with a special boot loader called PV-GRUB,

which starts the boot cycle and then chain loads the kernel specified in the menu.lst file on your image.

HVM boot by executing the master boot record of the root block device of your image.

Performance

PV guests had better performance than HVM guests in many cases,

but because of enhancements in HVM virtualization and

the availability of PV drivers for HVM AMIs, this is no longer true.

Instance Types

Unlimited mode(default): burstable, baseline(24-hour period), spikes

Baseline

t3.micro 10% (per vCPU)
t3.small 20% (per vCPU)
t3.medium 20% (per vCPU)
t3.large 30% (per vCPU)

Intel Xeon Platinum 8000 series processor (Turbo CPU clock speed of up to 3.1 GHz)

t3a

AMD EPYC 7000 series processor (Turbo clock speed of up to 2.5 GHz)

t4g

Arm-based

c5.xlarge $0.216 4C 8 GiB
t3.large $0.1168 2C 8 GiB
t3.xlarge $0.2336 4C 16 GiB

Web Console Tips

# search by tag Name

Name:MyTagName

AMI

Deregister your Linux AMI

When you deregister an AMI:

* it doesn't affect any instances that you've already launched from the AMI.

* it doesn't affect the snapshot(s) that were created for the volume(s) of the instance during the AMI creation process.

* You'll continue to incur storage costs for the snapshots.

Share an AMI with specific AWS accounts

OS AMI

Centos AWS

https://wiki.centos.org/Cloud/AWS

SSD storage

General Purpose

Baseline I/O performance for General Purpose SSD storage is 3 IOPS for each GiB, with a minimum of 100 IOPS.

Instances 's Credit specification

Instance can sustain high CPU utilization for any period of time whenever required.

Setting

T3 instances launch as unlimited by default.

It can be enabled or disabled at any time for a running or stopped instance.

Credits

If the average CPU usage over a 24-hour period exceeds the baseline, you incur charges for surplus credits.

When its CPU utilization falls below the baseline,

it uses the CPU credits that it earns to pay down the surplus credits that it spent earlier.

The hourly instance price automatically covers all CPU usage spikes

if the average CPU utilization of the instance is at or below the baseline over a rolling 24-hour period or

the instance lifetime, whichever is shorter.

1 CPU credit 相當於

One vCPU at 100% utilization for one minute
One vCPU at 50% utilization for two minutes
Two vCPUs at 25% utilization for two minutes

Earning CPU credits

t3.nano

CPU credits earned per hour: 6
Maximum earned credits that can be accrued: 144
vCPUs: 2
Baseline utilization per vCPU: 5%

t3.micro

CPU credits earned per hour: 12
Maximum earned credits that can be accrued: 288
vCPUs: 2
Baseline utilization per vCPU: 10%

Maximum earned credits that can be accrued:

相當於 24hr 內可以賺到幾多 credits

For T3 and T4g, the CPU credit balance persists for 7 days after an instance stops and the credits are lost thereafter.

Baseline utilization:

它是 Per vCPU

(number of credits earned/number of vCPUs)/60 minutes = %

i.e. t3.nano

6 / 2 / 60 = 5%

Credits Usage

Spent surplus credits are tracked by the CloudWatch metric CPUSurplusCreditBalance

CPUCreditUsage

CPUCreditBalance

T2/T3 Unlimited Mode Pricing

For T2 and T3 instances in Unlimited mode, CPU Credits are charged at per vCPU-hour

$0.05 per vCPU-Hour for Linux, RHEL and SLES
$0.096 per vCPU-Hour for Windows and Windows with SQL Web

When to use unlimited mode versus fixed CPU (breakeven CPU usage)

If a T3 instance continuously bursts at 100% CPU,

you end up paying approximately 1.5 times the price of an equivalently-sized M5 instance.

T3 instance 累計幾多 % CPU 後應選用 M5 instance

t3.large     42.5%
t3.xlarge     52.5%
t3.2xlarge     52.5%

ECUs 量

- ECU = EC2 Compute Unit
- processing power metric
- 引入原因: 不同 HW 有不同 vCPU 很難比較

Placement group

When you launch a new EC2 instance, the EC2 service attempts to spread out across underlying hardware

There is no charge for creating a placement group.

Cluster

packs instances close together inside an Availability Zone.
(low network latency)

* Start fails if there isn't enough capacity for the instance

Partition -

No two partitions within a placement group share the same racks
(Each rack has its own network and power source)

Spread

distinct underlying hardware

Capacity Reservation setting (open|none)

Capacity Reservation setting (open|none)

open - The instance can run in any open Capacity Reservation that has matching attributes
(instance type, platform, Availability Zone).

none - The instance avoids running in a Capacity Reservation even if one is available.

By creating Capacity Reservations

you ensure that you always have access to EC2 capacity when you need it,
for as long as you need it.
You can create Capacity Reservations at any time,
without entering into a one-year or three-year term commitment,
and the capacity is available immediately.
Billing starts as soon as the capacity is provisioned and the Capacity Reservation enters the active state.
When you no longer need it, cancel the Capacity Reservation to stop incurring charges.

To create a Capacity Reservation using the console

1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/

2. Choose Capacity Reservations, and then choose Create Capacity Reservation.

3. ...

Pricing

When the Capacity Reservation enters the active state,

you are charged the equivalent On-Demand rate whether you run instances in the reserved capacity or not.

Monitoring

Status Check Failed (Any)

Any = Instance || System

Status Check Failed (Instance)

Amazon EC2 checks the health of the instance by sending an
address resolution protocol (ARP) request to the network interface (NIC).

Status Check Failed (System)

Loss of network connectivity
Loss of system power
Software issues on the physical host
Hardware issues on the physical host

Disk metrics

Those metrics are not for EBS volumes, they are for instance store volumes.

For EBS volumes, see the metrics for the individual volumes.

Remark: instance store

An instance store provides temporary block-level storage for your instance.

This storage is located on disks that are physically attached to the host computer.

For caches, scratch data, and other temporary content

The virtual devices for instance store volumes are ephemeral[0-23]

You can't detach an instance store volume.
Instance store persists only during the lifetime of its associated instance. (Running)
You can't make an instance store volume available after you launch the instance.

Network in/out

in: The number of bytes received by the instance on all network interfaces.

out: The number of bytes sent out by the instance on all network interfaces.

Modify ‘Deletion on Termination’ flag for EBS volume

* The only way to do this is by using the AWS CLI

aws ec2 modify-instance-attribute --instance-id ID --block-device-mappings file://my.json

file://my.json

[
    {
    "DeviceName": "/dev/sda1",
    "Ebs": {
      "DeleteOnTermination": false
      }
    }
]

將 EBS 轉成加密

1. Create a snapshot for volume # On Volumes menu

2. Create an EBS volume from the unencrypted snapshot # On Snapshots menu

* 這時要選加密

3. Stop the EC2 instance

4. Detach the existing volume

5. Attach the new volume

6. Start the EC2 Instance

EC2 serial console

Error msg

This account is not authorized to use the EC2 serial console

To connect to this instance using the EC2 serial console, the account must be authorized in the EC2 account settings.

EC2 > Settings

user_data

When a user data script is processed, it is copied to and run from /var/lib/cloud/instances/instance-id/.
The script is not deleted after it is run and can be found in this directory with the name user-data.txt
So to check if your shell script made to the server refer this directory and the file.

The cloud-init output log file (/var/log/cloud-init-output.log) captures console output of your user_data shell script.

AWS prefix list

A managed prefix list is a set of one or more CIDR blocks.

可以在 security groups, route tables 使用

There are two types of prefix lists:

Customer-managed prefix lists
AWS-managed prefix lists

* You can modify a prefix list. When you add or remove entries, we create a new version of the prefix list.

* When you create a prefix list, you must specify the maximum number of entries(Max entries) that the prefix list can support.

* A prefix list applies only to the Region where you created it.

Max entries

if you create a prefix list with 20 maximum entries and

you reference that prefix list in a security group rule, this counts as 20 security group rules.

* The value must be greater than or equal to the number of prefix list entries.

Limit

Customer-managed Prefix lists per Region 100
Versions per prefix list 1,000

Check account id create instance

curl -s http://169.254.169.254/latest/dynamic/instance-identity/document | jq -r .accountId

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