Configuring iptables

DevOps Orchestration Platform provides additional security options at the operating system platform level in the form of iptables rules. To configure, click a VM instance button from the VirtualBox, AWS, or Google Cloud list (Figure 7); alternatively, navigate to a specific VM instance by selecting one from the expandable navigation column on the left side; then you can select the O/S Platform Firewall from a specific VM instance detail window.

Figure 7: Configuring iptables rules.

The Protocol -Port combinations are added as in the security group rules described earlier. As before, a button for a specific port on a specific row can be clicked to open or close a port.

SSH Connection to Instances

To SSH to a specific VM instance you can use either the SSH button in a row from the Managed VMs list or from the SSH button in the VM detail window. Either action launches an SSH window into the corresponding VM instance (Figure 8). As described earlier, in the case of AWS or GCP, ensure you have clicked the TEST button for each row of a newly deployed instance so the required data is pulled from the Terraform output and the SSH keys are configured. For convenience, the SSH window can also be detached into a separate window by clicking the Detach button.

Figure 8: Opening an SSH connection to a VM instance.

Deploying Sample Applications

Select a VM by clicking a VM instance button under VirtualBox, AWS (Managed VMs), or Google Cloud (Managed VMs) in the main window; alternatively, you can select a VM from the expandable navigation column on the left side.

General software applications and Linux utilities can be deployed by selecting from the drop-down list under the Generic Software Deployment section. Clicking Generate Inventory generates an Ansible inventory that is then stored in the corresponding deployment path on the back-end server filesystem as follows:

devops-orchestration-platform/devops_repo/ansible/<name_of_app>/inventory_<name_of_cloud_type>-<name_of_instance>

Selecting Deploy ensures an inventory is generated and then Ansible is run to deploy the application software onto the instance. Server application software can be deployed onto an instance under the Server Deployment section.

For some servers, such as DNS BIND9, the server needs to know what clients will access it. As shown in the Server Deployment section in Figure 9, a list of client VM instances can be selected for a particular server deployment. In the specific example shown, permission is given to three client nodes to access the DNS server.

Figure 9: Selecting the clients a server will service.

The purpose of the Client Deployment section is to deploy client software intended to access a service. For a specific client technology, it is critically important to select the server instance to which the client will send its requests. For example, if a DNS client is being deployed onto aws-vm-2, it will send its requests to the DNS server running on aws-vm-1, where aws-vm-1 is selected in the Select Server for Client drop-down.

DevOps Orchestration Platform includes a number of sample applications (see the "Sample Applications" box), along with their Ansible templates and playbooks. The Ansible inventories for these applications are dynamically generated at the infrastructure bootstrap stages described earlier (i.e., the framework facilitates a connection between Terraform and Ansible that is entirely invisible to the end user, who need only use the web application GUI).

The ELK sample playbook can deploy Elastic Stack (Filebeat, Logstash, ElasticSearch, and Kibana) onto arbitrary instances and configure them all to communicate together. After that, you can point your browser at Kibana to launch the dashboard (after opening the required ports in the Security Group configuration window for the corresponding default VPC). See the port window pop-up described later for assistance with this.

The Prometheus and Grafana sample playbook similarly installs Prometheus, Grafana, and the Node Exporter onto instances determined by the user from the GUI. If you then point a browser to the Grafana port on the Grafana VM instance, you will see the Grafana dashboards that were automatically installed and configured by the platform.

Ensuring the correct ports are opened on the default VPC's instances from the Security Groups or Firewall configuration feature – and likewise for iptables rules if iptables was deployed – is critically important.