Overview
Server v2.x Server Admin | CircleCI Server version 2.x is no longer a supported release. Please consult your account team for help in upgrading to a supported release. |
CircleCI server v2.x uses the CircleCI 2.0 architecture.version: 2.0 should be used in all .circleci/config.yml files.Currently not supported for Server: orbs, reusable commands, pipelines. |
CircleCI Server is a modern continuous integration and continuous delivery (CI/CD) platform installable inside your private cloud or data center. Refer to the Changelog for what’s new in this CircleCI server release.
Execution Environments
CircleCI uses Nomad as the primary job scheduler. Refer to our Introduction to Nomad Cluster Operation to learn more about the job scheduler and how to perform basic client and cluster operations.
By default, CircleCI Nomad clients automatically provision containers according to the image configured for each job in your .circleci/config.yml file.
Architecture
Figure 1.1 illustrates CircleCI core components, build orchestration services, and executors. The CircleCI API is a full-featured RESTful API that allows you to access all information and trigger all actions in CircleCI.
Within the CircleCI UI is the Insights page, which acts as a dashboard showing the health of all repositories you are following including:
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median build time
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median queue time
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last build time
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success rate
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parallelism
CircleCI consists of two primary components: Services and Nomad Clients. Any number of Nomad Clients execute your jobs and communicate back to the Services. All components must access GitHub or your hosted instance of GitHub Enterprise on the network, as illustrated below.
Services Machine
The Services machine must not be restarted and may be backed up using VM snapshotting. If you must restart the Services machine, do so only as a last resort, because a restart will result in downtime. Refer to the Backup and Recovery chapter for instructions.
DNS resolution may point to the IP address of the Services machine. It is also possible to point to a load balancer, for example an ELB in AWS. The following table describes the ports used for traffic on the Service machine:
| Source | Ports | Use |
|---|---|---|
End Users | 80, 443, 4434 | HTTP/HTTPS Traffic |
Administrators | 22 | SSH |
Administrators | 8800 | Admin Console |
Builder Boxes | all traffic, all ports | Internal Communication |
GitHub (Enterprise or .com) | 80, 443 | Incoming Webhooks |
Nomad Clients
Nomad Clients run without storing state, enabling you to increase or decrease the number of containers as needed.
To ensure enough Nomad clients are running to handle all builds, track the queued builds and increase the number of Nomad Client machines as needed to balance the load. For more on tracking metrics see Monitoring Your Installation.
Each machine reserves two vCPUs and 4GB of memory for coordinating builds. The remaining processors and memory create the containers. Larger machines are able to run more containers and are limited by the number of available cores after two are reserved for coordination.
| The maximum machine size for a Nomad client is 128GB RAM/ 64 CPUs, contact your CircleCI account representative to request use of larger machines for Nomad Clients. |
The following table describes the ports used on Nomad clients:
| Source | Ports | Use |
|---|---|---|
End Users | 64535-65535 | SSH into builds |
Administrators | 80 or 443 | CCI API Access |
Administrators | 22 | SSH |
Services Machine | all traffic, all ports | Internal Comms |
Nomad Clients (including itself) | all traffic, all ports | Internal Comms |
GitHub
CircleCI uses GitHub or GitHub Enterprise credentials for authentication which, in turn, may use LDAP, SAML, or SSH for access. This means CircleCI will inherit the authentication supported by your central SSO infrastructure.
| CircleCI does not support changing the URL or backend GitHub instance after it has been set up. The following table describes the ports used on machines running GitHub to communicate with the Services and Nomad Client instances. |
| Source | Ports | Use |
|---|---|---|
Services | 22 | Git Access |
Services | 80, 443 | API Access |
Nomad Client | 22 | Git Access |
Nomad Client | 80, 443 | API Access |
Help make this document better
This guide, as well as the rest of our docs, are open source and available on GitHub. We welcome your contributions.
- Suggest an edit to this page (please read the contributing guide first).
- To report a problem in the documentation, or to submit feedback and comments, please open an issue on GitHub.
- CircleCI is always seeking ways to improve your experience with our platform. If you would like to share feedback, please join our research community.
Need support?
Our support engineers are available to help with service issues, billing, or account related questions, and can help troubleshoot build configurations. Contact our support engineers by opening a ticket.
You can also visit our support site to find support articles, community forums, and training resources.
CircleCI Documentation by CircleCI is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
