Chapter 3: Management of Virtual Resources

Question 1

Difficulties in managing large sets of resources.

Answer 1

Provisioning of VMs and containers
Configuration of systems
Monitoring and failure handling
Replication and load balancing

Question 2

Remaining Problems in the Cloud Age.

Answer 2

server sprawl, configuration drift, snowflake servers

-> Technical debt!

Question 3

Manual configuration of servers usually leads to

Answer 3

• Configuration Drift: change configuration of single servers manually over time
• Snowflake Servers: Unique configuration, not reproducible

Question 4

Problems with unique Servers.

Answer 4

Failure, mirroring for testing, keeping cluster consistent

Question 5

Explain Infrastructure-as-a-Code.

Answer 5

Goal: Make systems easily reproducible.

One single source of truth with a clear declaration of host-specific configurationa -> infrastructure definition files

Question 6

Container Analogy: Advantages.

Answer 6

• Standardized
• Easy to move
• Isolated
• Many containers fit hosts

Question 7

Docker principle:

Answer 7

• Docker file: instructions for creating image
• Docker image: snapshot of a container with all dependencies
• Container instance: running isolated process, started form a image
  (sharing Host OS Kernel)

Question 8

Microservices (vs. Monolith)

Answer 8

Advantages
■ Independent
development
■ Small teams
■ Fault isolation
■ Scalable!

Disadvantages
■ Overhead (duplicated
tech)
■ Management of services and networking

Question 9

Purpose of Orchestration tools.

Answer 9

Control systems for clusters

Question 10

Main Orchestration tasks.

Answer 10

● Scheduling and placement
● Service configuration
● Networking and storage management 
● Monitoring and logging
● Replication and scaling
● Re-scheduling and load balancing
● Rolling updates

Question 11

Three parts of Devops. Seven Phases of DevOps.

Answer 11

• Development, Operations, Quality Assurance

- Plan, Create, Verify, Package, Release, Configure, Monitor

Question 12

Continuous Integration.

Answer 12

Automation of integration and testing of software

Question 13

Continuous Delivery.

Answer 13

Fast and reproducible software releases

Question 14

Continuous Delivery vs. Continuous Deployment.

Answer 14

C. Delivery: Deployment to Production manually

C. Deployment: Deployment to Production automatic

Question 15

Deployment Strategy

Answer 15

Blue/Green:
1. Deploy to the non-active environment
2. Switch the traffic coming through the load balancer
over to the new environment
3. Monitor new version, maybe switch back
-> easy roll-backs