1
Q
Snapshots, Volume, AMI
A
- Snapshots of Encrypted Volumes are encrypted automatically
- Volumes restored from encrypted snapshots are encryped automatically
- Snapshots can only be shared or make public when they are not encrypted.
- To guarantee consistency, stop the instances before taking snapshots of the root volumes.
- Root volume encryption can be done by snapshots, copy snapshots with encryption, create AMIs from encrypted snapshots, and lauch encrypted AMIs
2
Q
AMIs - EBS Root Device Volumes vs Instance Store
A
- Instance store volumes is Ephemeral Storage and can only be terminated;
- Instance store volumes can not create image;??
- EBS backed instances can be stopped and can choose to preserve data after instance termination
- AMI are regional
3
Q
Load Balancers
A
- Application Load balancer : Layer 7, intelligent, application aware, advanced request routing, route traffic to specific server.
- Network Load Balancer : Layer 4 ultra-low latency and extreme performance.
- Classic Load Balancer: Legacy, Layer4 or Layer 7; features like X-Forward-For (pass user’s IP address to instances), sticky sessions (statefull application).
- 504 error for timeout from App server or Database server.
4
Q
Cloudwatch
A
- Dashboards : Line,Stacked area, numbers, text ;
- Standard monitoring = 5 minutes
- Detailed monitoring = 1 minutes
- Alarms - Notifying a particular thresholds is hit.
- Events - State changes in your AWS resources.
- Logs - aggregate, monitor and store logs.
- Default metrics of EC2 : CPU, Disk, Network, StatusCheck
5
Q
Role and Credentials
A
Always using Roles inseand of Credentials.
6
Q
EC2 Placement Group
A
- Cluster placement group : Classic
- Low lentency, ultra throughput and network performance
- Singe AZ
- Spread placement group
- span multi AZ
- Instance type : Compute Optimized, GPU, Memory Optimized, Storage Optimized.
- Homogenous instances within placement group
- Exsisting instances can not be moved into a placement group. but we can create an AMI and laugh a instance from the AMI into the placement group.
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7
Q
Lambda - Runtime supporting
A
- C# :1.0 2.0 2.1
- Java : 8
- Go 1.x
- JSON 4.3 6.10 8.10
- Python 2.7 3.6
8
Q
Lambda - Pricing
A
- Number of requests : 1st Million free and $0.2 per Million thereafter.
- Duration:
- round up to the nearest 100ms
- 0.00001667$ per GB-second
9
Q
Lambda - features
A
- NO SERVERS!
- Continuous Scaling
- Super super super cheap!
10
Q
Serverless AWS service
A
- S3
- DynamoDB
- API Gateway
- Lambda
- SQS
- SNS
- Kenisis
11
Q
Lambda Exam Tips
A
- Continuous Scale out automatically
- Lambda functions and executions are independant, 1 event = 1 function.
- Serverless
- Can trigger other Lambda functions
- AWS X-ray to help to debug what is happening
- Can do things globally
12
Q
Lambda - Triggers
A
- AWS API
- S3
- DynamoDB
- Alexa
- Cloudwatch
- SNS
- SQS
- AWS IoT
- CloudFront
- AWS Smart home
- CodeCommit
- Cognito
13
Q
ParaVirtual vs Hardware Virtual Machine
A
- HVM support special extension of hardware so that OS can access the native hardware platform, hence better performance. Recommended
- PV is the old version of VIRTUALIZATION and used to support PV drivers exclusively achieving compatibilities and better performance. Now certain region and instance types support this mode.
- HVM boot from MBR, PV boot from PV-GRUB;
- PV on HVM drivers available to take advantage of both virtualization mode.
14
Q
EC2 Instance Types
A
FIGHT DR MC PX
15
Q
EBS Tips
A
Bootable
- SSD GP2： up to 10000 IOPS
- SSD Provisioned IOPS - IO1 >10000 IOPS
- HDD Magnetic - Standard - Cheap Less frequently Accessed workloads
Non bootable :
- HDD, Throughput Optimized - ST1 Frequently Accessed workloads
- HDD Cold - SC1- Less frequently Accessed workload
16
Q
Snapshot of RAID Array
A
- Freeze the volume : shutting down the APP
- umount the RAID Array
- Shutdown the EC2 Instance
- take snapshot
17
Q
EFS - NFSv4
A
- Scale up to petabytes
- PAYG
- thousands of concurrent NFS connections
- span across Multi-AZ
- Read after write consistency
