URL maps for routing in GCP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a URL map that directs traffic to a backend service.

GCP

gcloud compute url-maps create my-url-map --default-service [1]

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

Amy-backend-service

Bmy-firewall-rule

Cmy-instance-group

Dmy-network

Attempts:

3 left

💡 Hint

Common Mistakes

Using an instance group instead of a backend service.

Confusing firewall rules or networks as routing targets.

The --default-service flag requires the name of a backend service to route traffic to. Using an instance group, firewall rule, or network is incorrect here.

2fill in blank

medium

Complete the code to add a path matcher to the URL map for routing based on URL paths.

GCP

gcloud compute url-maps add-path-matcher my-url-map --default-service my-backend-service --path-matcher-name [1] --path-rules "/images/*=image-backend,/videos/*=video-backend"

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

Adefault-matcher

Bbackend-service

Cpath-matcher-1

Durl-map

Attempts:

3 left

💡 Hint

Common Mistakes

Using reserved or generic names that do not identify the path matcher.

Confusing the path matcher name with backend service names.

The --path-matcher-name flag requires a custom name for the path matcher. 'path-matcher-1' is a valid descriptive name.

3fill in blank

hard

Fix the error in the command to create a URL map with a host rule.

GCP

gcloud compute url-maps create my-url-map --default-service my-backend-service --host-rules [1]

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

A"hosts=example.com,pathMatcher=path-matcher-1"

Bhosts=example.com,pathMatcher=path-matcher-1

C"host=example.com,pathMatcher=path-matcher-1"

Dhost=example.com,pathMatcher=path-matcher-1

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the host rule string.

Using 'host' instead of 'hosts' in the key.

The --host-rules flag requires the value to be quoted and use the plural 'hosts' key. The correct format is a quoted string with 'hosts=' and 'pathMatcher=' keys.

4fill in blank

hard

Fill both blanks to define a URL map with a host rule and a path matcher.

GCP

gcloud compute url-maps create my-url-map --default-service [1] --host-rules "hosts=[2],pathMatcher=path-matcher-1"

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

Adefault-backend

Bexample.com

Cmy-backend-service

Dtest.com

Attempts:

3 left

💡 Hint

Common Mistakes

Using a domain name as the default service.

Using an incorrect or unrelated hostname in the host rule.

The default service should be a backend service name like 'my-backend-service'. The host rule should specify the hostname, here 'example.com'.

5fill in blank

hard

Fill all three blanks to add a path matcher with path rules to an existing URL map.

GCP

gcloud compute url-maps add-path-matcher my-url-map --path-matcher-name [1] --default-service [2] --path-rules "/api/*=[3]"

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

Aapi-matcher

Bapi-backend

Cbackend-api

Ddefault-backend

Attempts:

3 left

💡 Hint

Common Mistakes

Using inconsistent backend service names between default and path rules.

Choosing generic or unrelated names for the path matcher.

The path matcher name should be descriptive like 'api-matcher'. The default service and the backend for the path rule should be the backend service handling API traffic, here 'api-backend'.

Practice

1. What is the main purpose of a URL map in Google Cloud Platform's load balancing?

easy

A. To store user data for web applications

B. To create virtual machines automatically

C. To route incoming web traffic to different backend services based on URL paths or hosts

D. To monitor network traffic usage

Solution

1. Step 1: Understand URL map role

   A URL map directs web traffic to backend services depending on URL patterns.

2. Step 2: Identify correct function

   Routing based on URL paths or hosts matches the description of URL maps.

3. Final Answer:

   To route incoming web traffic to different backend services based on URL paths or hosts -> Option C

4. Quick Check:

   URL maps route traffic = B [OK]

Hint: URL maps decide backend by URL pattern [OK]

Common Mistakes:

• Confusing URL maps with storage or VM services
• Thinking URL maps monitor traffic instead of routing
• Assuming URL maps create resources automatically

2. Which of the following is the correct syntax to define a path matcher in a GCP URL map configuration?

easy

A. "pathMatcher": {"name": "pm1", "defaultService": "backend1"}

B. "pathMatchers": [{"name": "pm1", "defaultService": "backend1"}]

C. "pathMatchers": {"name": "pm1", "defaultService": "backend1"}

D. "pathMatcher": [{"name": "pm1", "defaultService": "backend1"}]

Solution

1. Step 1: Identify correct key for multiple path matchers

   The key for multiple path matchers is plural: "pathMatchers" with an array value.

2. Step 2: Confirm value type

   The value must be an array of objects, so square brackets [] are needed.

3. Final Answer:

   "pathMatchers": [{"name": "pm1", "defaultService": "backend1"}] -> Option B

4. Quick Check:

   Multiple path matchers use "pathMatchers" array = A [OK]

Hint: Use plural "pathMatchers" with array brackets [OK]

Common Mistakes:

• Using singular "pathMatcher" for multiple entries
• Using object instead of array for pathMatchers
• Mixing singular/plural keys incorrectly

3. Given this URL map snippet, which backend service will handle the request to https://example.com/images/logo.png?

{
  "defaultService": "backend-default",
  "pathMatchers": [
    {
      "name": "pm-images",
      "defaultService": "backend-images",
      "pathRules": [
        {"paths": ["/images/*"], "service": "backend-images"}
      ]
    }
  ]
}

medium

A. backend-images

B. No backend matches, request fails

C. backend-logo

D. backend-default

Solution

1. Step 1: Check path rules for "/images/*"

   The path matcher "pm-images" has a path rule matching "/images/*" directing to "backend-images".

2. Step 2: Match request URL path

   The request path "/images/logo.png" matches the "/images/*" pattern, so it routes to "backend-images".

3. Final Answer:

   backend-images -> Option A

4. Quick Check:

   Path "/images/*" matches request = backend-images [OK]

Hint: Match URL path to pathRules first, else defaultService [OK]

Common Mistakes:

• Choosing defaultService without checking pathRules
• Assuming no match causes failure instead of default routing
• Confusing path patterns with exact matches

4. You have this URL map configuration snippet:

{
  "defaultService": "backend-default",
  "pathMatchers": [
    {
      "name": "pm1",
      "defaultService": "backend1",
      "pathRules": [
        {"paths": ["/app/*"], "service": "backend-app"}
      ]
    }
  ]
}

Why does a request to https://example.com/app go to backend-default instead of backend-app?

medium

A. The defaultService overrides all pathRules

B. The path matcher name "pm1" is invalid

C. The backend service "backend-app" is not defined

D. The path "/app" does not match the pattern "/app/*" which requires a trailing slash

Solution

1. Step 1: Understand path pattern matching

   The pattern "/app/*" matches paths starting with "/app/" but not "/app" exactly.

2. Step 2: Check request path against pattern

   The request path "/app" lacks the trailing slash, so it does not match "/app/*" and falls back to defaultService.

3. Final Answer:

   The path "/app" does not match the pattern "/app/*" which requires a trailing slash -> Option D

4. Quick Check:

   Trailing slash matters in path patterns = C [OK]

Hint: Path patterns with * need trailing slash to match [OK]

Common Mistakes:

• Assuming "/app" matches "/app/*" without slash
• Thinking defaultService always overrides pathRules
• Believing backend service must be explicitly defined to route

5. You want to route requests to https://example.com/api/v1/users to backend-v1 and requests to https://example.com/api/v2/users to backend-v2. Which URL map configuration correctly achieves this?

hard

A. {
"defaultService": "backend-default",
"pathMatchers": [
{
"name": "pm-api",
"defaultService": "backend-default",
"pathRules": [
{"paths": ["/api/v1/*"], "service": "backend-v1"},
{"paths": ["/api/v2/*"], "service": "backend-v2"}
]
}
]
}

B. {
"defaultService": "backend-default",
"pathMatchers": [
{
"name": "pm-api",
"defaultService": "backend-v1",
"pathRules": [
{"paths": ["/api/v1/*"], "service": "backend-v1"},
{"paths": ["/api/v2/*"], "service": "backend-v2"}
]
}
]
}

C. {
"defaultService": "backend-default",
"pathMatchers": [
{
"name": "pm-api",
"defaultService": "backend-v2",
"pathRules": [
{"paths": ["/api/v1/*"], "service": "backend-v1"}
]
}
]
}

D. {
"defaultService": "backend-default",
"pathMatchers": [
{
"name": "pm-api",
"defaultService": "backend-default",
"pathRules": [
{"paths": ["/api/*"], "service": "backend-v1"},
{"paths": ["/api/*"], "service": "backend-v2"}
]
}
]
}

Solution

1. Step 1: Check path rules for specific version routing

   { "defaultService": "backend-default", "pathMatchers": [ { "name": "pm-api", "defaultService": "backend-default", "pathRules": [ {"paths": ["/api/v1/*"], "service": "backend-v1"}, {"paths": ["/api/v2/*"], "service": "backend-v2"} ] } ] } defines two distinct path rules: "/api/v1/*" to "backend-v1" and "/api/v2/*" to "backend-v2" which matches requirements.

2. Step 2: Verify defaultService and pathRules consistency

   { "defaultService": "backend-default", "pathMatchers": [ { "name": "pm-api", "defaultService": "backend-default", "pathRules": [ {"paths": ["/api/v1/*"], "service": "backend-v1"}, {"paths": ["/api/v2/*"], "service": "backend-v2"} ] } ] } uses "backend-default" as defaultService, so unmatched paths go there, which is correct.

3. Step 3: Identify issues in other options

   { "defaultService": "backend-default", "pathMatchers": [ { "name": "pm-api", "defaultService": "backend-v1", "pathRules": [ {"paths": ["/api/v1/*"], "service": "backend-v1"}, {"paths": ["/api/v2/*"], "service": "backend-v2"} ] } ] } sets defaultService to "backend-v1" which may misroute unmatched paths. { "defaultService": "backend-default", "pathMatchers": [ { "name": "pm-api", "defaultService": "backend-v2", "pathRules": [ {"paths": ["/api/v1/*"], "service": "backend-v1"} ] } ] } misses "/api/v2/*" pathRule. { "defaultService": "backend-default", "pathMatchers": [ { "name": "pm-api", "defaultService": "backend-default", "pathRules": [ {"paths": ["/api/*"], "service": "backend-v1"}, {"paths": ["/api/*"], "service": "backend-v2"} ] } ] } duplicates "/api/*" paths causing conflict.

4. Final Answer:

   Option A correctly routes /api/v1/* and /api/v2/* to respective backends -> Option A

5. Quick Check:

   Distinct pathRules for versions = A [OK]

Hint: Use distinct pathRules for each version prefix [OK]

Common Mistakes:

• Setting defaultService to one version backend
• Missing pathRule for one version
• Duplicating same path pattern causing conflicts