Cloud Logging overview in GCP - Commands & Configuration

Introduction

Cloud Logging helps you collect and view logs from your applications and services in one place. It solves the problem of finding and understanding what happened in your cloud environment by organizing logs clearly.

When you want to see error messages from your app running on Google Cloud.

When you need to track user activity or system events for security checks.

When you want to monitor performance issues by reviewing logs over time.

When you want to create alerts based on specific log messages.

When you need to export logs to storage or analysis tools for deeper insights.

Commands

This command writes a test log entry with INFO severity to a log named 'my-log'. It helps verify that logging is working.

Terminal

gcloud logging write my-log "This is a test log entry" --severity=INFO

Expected Output

Created log entry.

→

--severity - Sets the importance level of the log entry.

This command reads the last 5 entries from the 'my-log' log in descending order to see recent log messages.

Terminal

gcloud logging read "logName=projects/my-project/logs/my-log" --limit=5 --order=desc

Expected Output

[

  {

    "textPayload": "This is a test log entry",

    "severity": "INFO",

    "logName": "projects/my-project/logs/my-log"

  }

]

→

--limit - Limits the number of log entries returned.

→

--order - Orders the log entries by newest first.

This command creates a sink named 'my-sink' that exports all ERROR and higher severity logs to a Cloud Storage bucket named 'my-bucket'.

Terminal

gcloud logging sinks create my-sink storage.googleapis.com/my-bucket --log-filter="severity>=ERROR"

Expected Output

Created sink [my-sink].

→

--log-filter - Filters logs to export only those with severity ERROR or higher.

This command lists all log names available in the project so you can see what logs exist.

Terminal

gcloud logging logs list

Expected Output

my-log

cloudaudit.googleapis.com%2Factivity

compute.googleapis.com%2Finstance

Key Concept

If you remember nothing else from this pattern, remember: Cloud Logging collects and organizes logs so you can easily find and understand what happened in your cloud services.

Common Mistakes

Not specifying the correct project when running gcloud logging commands.

Logs belong to specific projects, so commands run in the wrong project won't show or write the expected logs.

Use 'gcloud config set project my-project' to set the right project before running logging commands.

Using incorrect log names or filters when reading or exporting logs.

If the log name or filter is wrong, you won't see the logs you expect or export the right data.

Double-check log names and use simple filters first to confirm logs exist before applying complex filters.

Summary

Use 'gcloud logging write' to add log entries manually for testing or custom logs.

Use 'gcloud logging read' to view recent logs with filters and limits.

Create sinks to export logs to storage or other services for analysis.

List logs to discover what logs are available in your project.

Practice

1. What is the main purpose of Cloud Logging in Google Cloud Platform?

easy

A. To store large files in the cloud

B. To create virtual machines automatically

C. To manage user permissions and roles

D. To collect and display logs from cloud resources in one place

Solution

1. Step 1: Understand Cloud Logging's role

   Cloud Logging collects logs from various cloud resources and shows them centrally.

2. Step 2: Compare options with this role

   Only To collect and display logs from cloud resources in one place describes collecting and displaying logs; others describe unrelated services.

3. Final Answer:

   To collect and display logs from cloud resources in one place -> Option D

4. Quick Check:

   Cloud Logging = centralized log collection [OK]

Hint: Cloud Logging is about logs, not VMs or storage [OK]

Common Mistakes:

• Confusing logging with VM creation
• Thinking it manages user permissions
• Mixing it up with storage services

2. Which of the following is the correct gcloud command to read logs from Cloud Logging?

easy

A. gcloud logging read "resource.type=gae_app"

B. gcloud compute instances list

C. gcloud storage buckets create my-bucket

D. gcloud iam roles describe admin

Solution

1. Step 1: Identify the command for reading logs

   The command to read logs uses 'gcloud logging read' followed by a filter.

2. Step 2: Check each option

   gcloud logging read "resource.type=gae_app" uses 'gcloud logging read' correctly; others relate to compute, storage, or IAM.

3. Final Answer:

   gcloud logging read "resource.type=gae_app" -> Option A

4. Quick Check:

   Log reading command starts with 'gcloud logging read' [OK]

Hint: Look for 'logging read' in the command to find logs [OK]

Common Mistakes:

• Using compute or storage commands instead of logging
• Missing the 'read' keyword after 'logging'
• Confusing IAM commands with logging commands

3. What will be the output of this command?
gcloud logging read "severity=ERROR" --limit 2 --format json

medium

A. A JSON list of the 2 most recent ERROR severity log entries

B. A list of all logs regardless of severity

C. An error message about invalid command syntax

D. A list of 2 logs with severity INFO

Solution

1. Step 1: Understand the command parameters

   The command reads logs filtered by severity=ERROR, limits output to 2 entries, and formats output as JSON.

2. Step 2: Analyze expected output

   It returns a JSON list of the 2 most recent logs with ERROR severity, not all logs or INFO logs.

3. Final Answer:

   A JSON list of the 2 most recent ERROR severity log entries -> Option A

4. Quick Check:

   Filter + limit + JSON format = filtered JSON logs [OK]

Hint: Filter by severity and limit controls output count [OK]

Common Mistakes:

• Ignoring the severity filter
• Expecting all logs instead of limited ones
• Confusing severity levels

4. You run this command but get no output:
gcloud logging read "severity=CRITICAL" --limit 5
What is the most likely reason?

medium

A. The command syntax is incorrect

B. There are no logs with severity CRITICAL in the selected time range

C. The gcloud tool is not installed

D. The limit flag cannot be used with severity filters

Solution

1. Step 1: Check command syntax

   The command syntax is correct; 'gcloud logging read' supports severity filters and limit.

2. Step 2: Consider reasons for no output

   No output usually means no matching logs exist for severity CRITICAL in the default time range.

3. Final Answer:

   There are no logs with severity CRITICAL in the selected time range -> Option B

4. Quick Check:

   No output often means no matching logs [OK]

Hint: No output? Check if logs exist for that severity [OK]

Common Mistakes:

• Assuming syntax error without checking
• Thinking limit flag is invalid with filters
• Ignoring that no logs might exist

5. You want to monitor your app's logs for errors and send alerts only when ERROR or higher severity logs appear. Which Cloud Logging feature should you use?

hard

A. Create a VM instance to process logs locally

B. Use Cloud Storage to save logs and check manually

C. Create a log-based metric with a filter for severity >= ERROR and set up an alerting policy

D. Run gcloud logging read manually every hour

Solution

1. Step 1: Identify monitoring and alerting needs

   You want automatic alerts on ERROR or higher severity logs.

2. Step 2: Match features to needs

   Log-based metrics with filters and alerting policies automate monitoring and alerts.

3. Step 3: Evaluate other options

   Manual checks or storing logs without alerts do not meet the requirement.

4. Final Answer:

   Create a log-based metric with a filter for severity >= ERROR and set up an alerting policy -> Option C

5. Quick Check:

   Log-based metrics + alerts = automated error monitoring [OK]

Hint: Use log-based metrics and alerts for automatic error notifications [OK]

Common Mistakes:

• Relying on manual log checks
• Using storage without alerting
• Creating unrelated VM instances