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I'm doing a deployment of 4 CE in 2 different zones (bastion in europe-west1-c and the other ones in europe-west2-c). I can ssh from cassandra-node-1 to cassandra-node-2 just using the hostname:

pedro_gordo_gmail_com@cassandra-node-1:~$ ssh cassandra-node-2
Welcome to Ubuntu 16.04.6 LTS (GNU/Linux 4.15.0-1049-gcp x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage


0 packages can be updated.
0 updates are security updates.

New release '18.04.3 LTS' available.
Run 'do-release-upgrade' to upgrade to it.


Last login: Sun Dec  1 13:48:17 2019 from 10.154.0.14
groups: cannot find name for group ID 926993188

But I can't do the same from the bastion CE:

pedro_gordo_gmail_com@bastion:~$ ssh cassandra-node-1
ssh: Could not resolve hostname cassandra-node-1: Name or service not known

But I can ssh using the internal/external IP:

pedro_gordo_gmail_com@bastion:~$ ssh 10.154.0.14
Welcome to Ubuntu 16.04.6 LTS (GNU/Linux 4.15.0-1049-gcp x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

 * Overheard at KubeCon: "microk8s.status just blew my mind".

     https://microk8s.io/docs/commands#microk8s.status

0 packages can be updated.
0 updates are security updates.

New release '18.04.3 LTS' available.
Run 'do-release-upgrade' to upgrade to it.


Last login: Sun Dec  1 13:48:10 2019 from 173.194.92.32
groups: cannot find name for group ID 926993188

According to this GCP documentation, if I choose a custom name for my CE, then I need to edit the DNS. But on the other hand, if I don't provide a name: in my deployment-manager config, then I get the following error when I try to deploy:

gcloud deployment-manager deployments create cluster --config create-vms.yaml
ERROR: (gcloud.deployment-manager.deployments.create) ResponseError: code=412, message=Missing resource name in resource "type: compute.v1.instance

This is my deployment-manager configuration. How can I change this so that I can ssh from bastion to cassandra-node-1/2/3 just using the hostname? 

# Copyright 2016 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Import all templates used in deployment

# Declare all resources. In this case, one highly available service
# as defined in the ha-service.py template.
resources:
- type: compute.v1.instance
  name: bastion
  properties:
    zone: europe-west1-c
    machineType: https://www.googleapis.com/compute/v1/projects/affable-seat-213016/zones/europe-west1-c/machineTypes/n1-standard-1
    disks:
    - deviceName: boot
      boot: true
      autoDelete: true
      initializeParams:
        sourceImage: https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1604-xenial-v20190514
    networkInterfaces:
    - accessConfigs:
      - name: External NAT
        type: ONE_TO_ONE_NAT
    metadata:
      items:
      - key: startup-script
        value: |
          #!/bin/bash
          sudo apt-add-repository -y ppa:ansible/ansible
          sudo apt-get update
          sudo apt-get install -y ansible
- type: compute.v1.instance
  name: cassandra-node-1
  properties:
    zone: europe-west2-c
    machineType: https://www.googleapis.com/compute/v1/projects/affable-seat-213016/zones/europe-west2-c/machineTypes/n1-standard-1 
    disks:
    - deviceName: boot
      boot: true
      autoDelete: true
      initializeParams:
        sourceImage: https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1604-xenial-v20190514
    - deviceName: data
      boot: false
      autoDelete: true
      initializeParams:
        diskSizeGb: 1
        diskType: zones/europe-west2-c/diskTypes/pd-ssd
    networkInterfaces:
    - accessConfigs:
      - name: External NAT
        type: ONE_TO_ONE_NAT
- type: compute.v1.instance
  name: cassandra-node-2
  properties:
    zone: europe-west2-c
    machineType: projects/affable-seat-213016/zones/europe-west2-c/machineTypes/n1-standard-1
    disks:
    - deviceName: boot
      boot: true
      autoDelete: true
      initializeParams:
        sourceImage: https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1604-xenial-v20190514
    - deviceName: data                                                                                                                                                                              
      boot: false
      autoDelete: true
      initializeParams:
        diskSizeGb: 1
        diskType: zones/europe-west2-c/diskTypes/pd-ssd
    networkInterfaces:
    - accessConfigs:
      - name: External NAT
        type: ONE_TO_ONE_NAT
- type: compute.v1.instance
  name: cassandra-node-3
  properties:
    zone: europe-west2-c
    machineType: https://www.googleapis.com/compute/v1/projects/affable-seat-213016/zones/europe-west2-c/machineTypes/n1-standard-1
    disks:
    - deviceName: boot
      boot: true
      autoDelete: true
      initializeParams:
        sourceImage: https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1604-xenial-v20190514
    - deviceName: data
      boot: false
      autoDelete: true
      initializeParams:
        diskSizeGb: 1
        diskType: zones/europe-west2-c/diskTypes/pd-ssd
    networkInterfaces:
    - accessConfigs:
      - name: External NAT
        type: ONE_TO_ONE_NAT
Pedro Gordo
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1 Answers1

2

You have two solutions:

  1. Use Google Cloud DNS and set up a private zone to resolve hostnames for your VPC.
  2. Use the Compute Engine internal DNS name.

However, for method #2, I do not remember if hostname resolution for internal names is resolved across zones as the Compute Engine internal DNS is used for name resolution. Method #1 will always work provided that DNS is set up correctly.

John Hanley
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  • If I understood correctly from the documentation, to use #2 I need to leave the default name for the CE. However, it doesn't seem like Deployment Manager accepts configurations without names for the CE instances (check the question at the bottom of my post). Is there any way around this? – Pedro Gordo Dec 02 '19 at 21:21
  • I think you are getting the initial error because you need to specify the 'name'(INSTANCE_NAME) in the yaml file which is something that you cannot avoid. However, have you tried editing the same yaml file by adding a field for 'hostname' as mentioned [here](https://cloud.google.com/compute/docs/instances/custom-hostname-vm#create_a_vm_with_a_custom_hostname) and then try to [establish a connection](https://cloud.google.com/compute/docs/instances/connecting-advanced#bastion_host) through the bastion host – Digil Dec 03 '19 at 20:20