cloud engineer
How to add startup and shutdown scripts on GCP Compute Engine.
Startup Script
gcloud compute instances add-metadata servername \ --project project-id \ --zone us-central1-c \ --metadata=startup-script='#! /bin/bash sudo -i echo "Time: $(date)" >> /tmp/date.txt' |
gcloud compute instances add-metadata servername \ --project project-id \ --zone us-central1-c \ --metadata=startup-script='#! /bin/bash sudo -i echo "Time: $(date)" >> /tmp/date.txt'
Shutdown Script
gcloud compute instances add-metadata servername \ --project project-id \ --zone us-central1-c \ --metadata=shutdown-script='#! /bin/bash # Shuts down Apache server /etc/init.d/apache2 stop' |
gcloud compute instances add-metadata servername \ --project project-id \ --zone us-central1-c \ --metadata=shutdown-script='#! /bin/bash # Shuts down Apache server /etc/init.d/apache2 stop'
How to add a startup-script to metadata. The script executes every time VM is started.
gcloud compute instances add-metadata instance-name \ --project your-project-id \ --zone us-central1-c \ --metadata=startup-script='#! /bin/bash sudo -i echo "Time: $(date)" >> /tmp/date.txt' |
gcloud compute instances add-metadata instance-name \ --project your-project-id \ --zone us-central1-c \ --metadata=startup-script='#! /bin/bash sudo -i echo "Time: $(date)" >> /tmp/date.txt'
Here’s the metadata URLs for both AWS and GCP.
curl http://169.254.169.254/computeMetadata/v1/ -H "Metadata-Flavor: Google" curl http://169.254.169.254/latest/meta-data/ |
curl http://169.254.169.254/computeMetadata/v1/ -H "Metadata-Flavor: Google" curl http://169.254.169.254/latest/meta-data/
If you are getting this return code [1] error, check if enable-oslogin metadata is set to TRUE in your VM.
Here’s the error when logging in.
gcloud compute ssh your-server-name \ --zone us-central1-a \ --project your-project-id \ --internal-ip & ERROR: (gcloud.compute.ssh) [C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\bin\sdk\plink.exe] exited with return code [1]. |
gcloud compute ssh your-server-name \ --zone us-central1-a \ --project your-project-id \ --internal-ip & ERROR: (gcloud.compute.ssh) [C:\Program Files (x86)\Google\Cloud SDK\google-cloud-sdk\bin\sdk\plink.exe] exited with return code [1].
Remove metadata.
gcloud compute instances remove-metadata your-server-name \ --keys=enable-oslogin \ --zone us-central1-a \ --project your-project-id Updated [https://www.googleapis.com/compute/v1/projects/your-project-id/zones/us-central1-a/instances/your-server-name]. |
gcloud compute instances remove-metadata your-server-name \ --keys=enable-oslogin \ --zone us-central1-a \ --project your-project-id Updated [https://www.googleapis.com/compute/v1/projects/your-project-id/zones/us-central1-a/instances/your-server-name].
Run gcloud ssh again.
gcloud compute ssh your-server-name \ --zone us-central1-a \ --project your-project-id \ --internal-ip & [1] 1257 |
gcloud compute ssh your-server-name \ --zone us-central1-a \ --project your-project-id \ --internal-ip & [1] 1257
This time it opens up a Putty session and you’re able to login.
How to update an instance metadata in GCP.
gcloud compute instances add-metadata instance-name \ --metadata key-name=value \ --project your-project-id \ --zone us-central1-a |
gcloud compute instances add-metadata instance-name \ --metadata key-name=value \ --project your-project-id \ --zone us-central1-a
In this example, we are adding enable-oslogin=TRUE.
gcloud compute instances add-metadata instance-name \ --metadata enable-oslogin=TRUE \ --project your-project-id \ --zone us-central1-a |
gcloud compute instances add-metadata instance-name \ --metadata enable-oslogin=TRUE \ --project your-project-id \ --zone us-central1-a
Here’s a quick script to stand up a web server based on Centos image.
gcloud compute instances create [VM-NAME] \ --zone=[ZONE] \ --image-family=debian-9 \ --image-project=debian-cloud \ --tags=allow-ssh,allow-health-check \ --subnet=lb-subnet \ --metadata=startup-script='#! /bin/bash apt-get update apt-get install apache2 -y a2ensite default-ssl a2enmod ssl vm_hostname="$(curl -H "Metadata-Flavor:Google" \ http://169.254.169.254/computeMetadata/v1/instance/name)" echo "Page served from: $vm_hostname" | \ tee /var/www/html/index.html systemctl restart apache2' |
gcloud compute instances create [VM-NAME] \ --zone=[ZONE] \ --image-family=debian-9 \ --image-project=debian-cloud \ --tags=allow-ssh,allow-health-check \ --subnet=lb-subnet \ --metadata=startup-script='#! /bin/bash apt-get update apt-get install apache2 -y a2ensite default-ssl a2enmod ssl vm_hostname="$(curl -H "Metadata-Flavor:Google" \ http://169.254.169.254/computeMetadata/v1/instance/name)" echo "Page served from: $vm_hostname" | \ tee /var/www/html/index.html systemctl restart apache2'
How to display IP address and Instance ID on web page behind a AWS load balancer.
Add these 2 commands in crontab. The job runs every 5 mins.
*/5 * * * * /usr/bin/curl http://169.254.169.254/latest/meta-data/instance-id > /var/www/html/id.txt */5 * * * * /usr/bin/curl http://169.254.169.254/latest/meta-data/public-ipv4 > /var/www/html/ip.txt |
*/5 * * * * /usr/bin/curl http://169.254.169.254/latest/meta-data/instance-id > /var/www/html/id.txt */5 * * * * /usr/bin/curl http://169.254.169.254/latest/meta-data/public-ipv4 > /var/www/html/ip.txt
You can view on the site.
# your domain http://yourdomain.com/ip.txt http://yourdomain.com/id.txt # your server ip address http://1.1.1.1/ip.txt http://1.1.1.1/id.txt |
# your domain http://yourdomain.com/ip.txt http://yourdomain.com/id.txt # your server ip address http://1.1.1.1/ip.txt http://1.1.1.1/id.txt