Blue-green deployment in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the two environments used in blue-green deployment.

Microservices

environments = ['[1]', 'green']

Drag options to blanks, or click blank then click option'

Ayellow

Bred

Cblue

Dpurple

Attempts:

3 left

💡 Hint

Common Mistakes

Using colors other than blue for the first environment.

Blue-green deployment uses two identical environments named 'blue' and 'green'.

2fill in blank

medium

Complete the code to switch traffic to the new environment in blue-green deployment.

Microservices

current_live_env = '[1]'

Drag options to blanks, or click blank then click option'

Agreen

Bblue

Cred

Dyellow

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing the live environment with the inactive one.

After deployment, traffic is switched to the 'green' environment to make it live.

3fill in blank

hard

Fix the error in the code that updates the live environment after deployment.

Microservices

live_env = '[1]'  # Should be the environment receiving traffic

Drag options to blanks, or click blank then click option'

Ablue

Bred

Cyellow

Dgreen

Attempts:

3 left

💡 Hint

Common Mistakes

Setting live environment to the old inactive environment.

The live environment should be the one receiving traffic, which is 'green' after deployment.

4fill in blank

hard

Fill both blanks to create a dictionary mapping environments to their status.

Microservices

env_status = {'blue': '[1]', 'green': '[2]'}

Drag options to blanks, or click blank then click option'

Aactive

Binactive

Cpending

Dfailed

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up active and inactive statuses.

In blue-green deployment, one environment is 'active' (live) and the other is 'inactive' (standby).

5fill in blank

hard

Fill all three blanks to complete the deployment switch logic.

Microservices

if current_env == '[1]':
    next_env = '[2]'
else:
    next_env = '[3]'

Drag options to blanks, or click blank then click option'

Ablue

Bgreen

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same environment for both next_env assignments.

The logic switches from 'blue' to 'green', or from 'green' back to 'blue'.

Practice

1. What is the main purpose of blue-green deployment in microservices?

easy

A. To improve database query speed

B. To increase the number of microservices in the system

C. To reduce downtime by switching traffic between two identical environments

D. To simplify the codebase by merging services

Solution

1. Step 1: Understand blue-green deployment concept

   Blue-green deployment uses two identical environments to avoid downtime during updates.

2. Step 2: Identify the main goal

   The main goal is to switch traffic between environments to keep the system available without interruption.

3. Final Answer:

   To reduce downtime by switching traffic between two identical environments -> Option C

4. Quick Check:

   Blue-green deployment = reduce downtime [OK]

Hint: Blue-green means two environments for zero downtime [OK]

Common Mistakes:

• Confusing deployment with scaling
• Thinking it improves database speed
• Assuming it merges microservices

2. Which of the following is the correct sequence in a blue-green deployment?

easy

A. Deploy to green, test, switch traffic from blue to green

B. Deploy to blue, switch traffic, then test on green

C. Switch traffic first, then deploy to blue

D. Deploy to green, switch traffic, then test on blue

Solution

1. Step 1: Recall deployment steps

   In blue-green deployment, new code is deployed to the inactive environment (green).

2. Step 2: Test and switch traffic

   After testing green, traffic is switched from blue (active) to green (new).

3. Final Answer:

   Deploy to green, test, switch traffic from blue to green -> Option A

4. Quick Check:

   Deploy-test-switch = A [OK]

Hint: Deploy to inactive env, test, then switch traffic [OK]

Common Mistakes:

• Switching traffic before testing
• Testing on active environment
• Deploying after switching traffic

3. Consider this simplified code snippet for switching traffic in blue-green deployment:

current_env = "blue"
new_env = "green"
if current_env == "blue":
    current_env = new_env
else:
    current_env = "blue"
print(current_env)

What will be the output?

medium

A. "blue"

B. None

C. SyntaxError

D. "green"

Solution

1. Step 1: Analyze initial variables

   current_env starts as "blue", new_env is "green".

2. Step 2: Evaluate the if condition

   Since current_env == "blue", it sets current_env = new_env, which is "green".

3. Final Answer:

   "green" -> Option D

4. Quick Check:

   Switching from blue to green prints green [OK]

Hint: If current is blue, switch to green [OK]

Common Mistakes:

• Confusing assignment direction
• Expecting original value to print
• Thinking code has syntax error

4. A team uses blue-green deployment but users report downtime during the switch. What is the most likely cause?

medium

A. The old environment was not shut down

B. Traffic was switched before the new environment was fully ready

C. The database was not updated

D. The new environment was tested too long

Solution

1. Step 1: Understand downtime cause in blue-green

   Downtime usually happens if traffic switches before the new environment is ready to serve requests.

2. Step 2: Evaluate options

   Old environment running or database update issues don't cause immediate downtime during switch; testing too long delays deployment but not downtime.

3. Final Answer:

   Traffic was switched before the new environment was fully ready -> Option B

4. Quick Check:

   Premature traffic switch = downtime [OK]

Hint: Switch traffic only after new env is ready [OK]

Common Mistakes:

• Assuming old env causes downtime
• Ignoring readiness checks
• Blaming database updates for switch downtime

5. You manage a critical microservices system using blue-green deployment. After switching traffic to green, you discover a severe bug. What is the best immediate action to minimize downtime?

hard

A. Switch traffic back to blue environment immediately

B. Fix the bug in green environment and keep traffic there

C. Restart both environments simultaneously

D. Deploy a new environment and switch traffic there

Solution

1. Step 1: Understand rollback in blue-green deployment

   Blue-green allows quick rollback by switching traffic back to the previous stable environment (blue).

2. Step 2: Evaluate options for minimizing downtime

   Fixing bug in green delays recovery; restarting both causes downtime; deploying new environment takes time.

3. Final Answer:

   Switch traffic back to blue environment immediately -> Option A

4. Quick Check:

   Rollback by switching traffic = minimize downtime [OK]

Hint: Rollback by switching traffic to old env fast [OK]

Common Mistakes:

• Trying to fix bug before rollback
• Restarting both environments causing downtime
• Deploying new env wastes time