CircleCI Server v3.x Overview
Server v3.x Server Admin Introduction
CircleCI server is an on-premises CI/CD platform for enterprise customers who have compliance or security needs that require them to operate within their firewall, in a private cloud, or in a data center.
Server provides the same features as CircleCI’s cloud offering, but operates within your Kubernetes cluster.
The CircleCI server application exposes four services, using load balancers. Three of these load balancers are VPC (Virtual Private Cloud)-internal for connecting to the Nomad cluster and virtual machines. If required, the front-end load balancer can be made private, separating it from the public internet. For further information see the Load Balancers doc.
| Load Balancer | Type | Ports | Description |
|---|---|---|---|
Frontend GUI Proxy & API | External | 80 and 443 | Exposes the web application. |
Nomad Control Plane | Internal | 4647 | Exposes an RPC protocol for Nomad runners. |
Output Processor | Internal | 8585 | Ingests output from Nomad runners. |
VM Service | Internal | 3000 | Provisions virtual machines. |
The application exposes a number of external ports. These ports are used for various functions as defined in the table below.
| Port number | Protocol | Direction | Source / Destination | Use | Notes |
|---|---|---|---|---|---|
80 | TCP | Inbound | End users | HTTP web app traffic | |
443 | TCP | Inbound | End users | HTTP web app traffic | |
8800 | TCP | Inbound | Administrators | Admin console | |
22 | TCP | Inbound | Administrators | SSH | Only required for the bastion host. |
64535-65535 | TCP | Inbound | SSH into builds | Only required for the Nomad clients. |
CircleCI server schedules CI jobs using the Nomad scheduler. The Nomad control plane runs inside of Kubernetes, while the Nomad clients, which are responsible for running scheduled CircleCI jobs, are provisioned outside the cluster. CircleCI server can run Docker jobs on the Nomad clients themselves or in a dedicated virtual machine (VM).
Job artifacts and outputs are sent directly from jobs in Nomad to object storage (S3, GCS, or other supported options). Audit logs and other items from the application are also stored in object storage, so both the Kubernetes cluster and the Nomad clients need access to object storage.
Services
CircleCI server 3.0 consists of the following services. Find their descriptions and failure implications below:
| Service | Component | Description | What happens if it fails? | Notes |
|---|---|---|---|---|
api-service | App Core | Provides a GraphQL API that provides data to render the web frontend. | Many parts of the UI (such as Contexts) will fail completely. | |
audit-log-service | App Core | Persists audit log events to blob storage for long-term storage. | Some events may not be recorded. | |
builds-service | App Core | Ingests from www-api and sends to plans-service, workflows-conductor, and to orbs-service. | ||
circleci-mongodb | Execution | Primary datastore | ||
circleci-postgres | Data storage for microservices | |||
circleci-rabbitmq | Pipelines and Execution | Queuing for workflow messaging, test results, usage, crons, output, notifications, and scheduler. | ||
circleci-redis | Execution | Caches data that will not be stored permanently (such as build logs), for request caching, and for rate limit calculations. | A failed cache can result in rate limiting from the VCS if too many calls are made to it. | |
circleci-telegraf | Telegraf collects statsd metrics. All white-boxed metrics in our services publish statsd metrics that are sent to telegraf, but can also be configured to be exported to other places (such as Datadog or Prometheus). | |||
circleci-vault | HashiCorp Vault to run encryption and decryption as a service for secrets. | |||
config | ||||
contexts-service | App Core | Stores and provides encrypted contexts. | All builds using Contexts will fail. | |
cron-service | Pipelines | Triggers scheduled workflows. | Scheduled workflows will not run. | |
dispatcher | Execution | Split jobs into tasks and send them to scheduler to run. | No jobs will be sent to Nomad. The run queue will increase in size, but there should be no meaningful loss of data. | |
domain-service | App Core | Stores and provides information about our domain model. Works with permissions and API. | Workflows will fail to start and some REST API calls may fail, causing 500 errors in the CircleCI UI. If LDAP authentication is in use, all logins will fail. | |
exim | Will be removed in GA, but users can provide mail submission credentials to an existing MTA. | No email notifications will be sent. | ||
frontend | Frontend | CircleCI web app and www-api proxy. | The UI and REST API will be unavailable and no jobs will be triggered by GitHub/Enterprise. Running builds will be OK, but no updates will be seen. | Rate limit of 150 requests per second with a single user instantaneous limit of 300 requests. |
inject-bottoken | A Kubernetes job that inserts a "bot token" into MongoDB. Bot tokens are authorization interservice communication. | Mainly for www-api | ||
kotsadm-kots | Licensing | The main KOTS application. Runs the KOTS Admin Console, where upgrades and server configuration take place. | No upgrades or configuration possible for server. No admin console available. | |
kotsadm-migrations | Licensing | Performs database migrations to handle updates of Kotsadm. | ||
kotsadm-minio | Licensing | Object storage for KOTS licensing. | ||
kotsadm-postgres | Licensing | Database for KOTS licensing. | ||
legacy-notifier | App Core | Handles notifications to external services (for example, Slack or email). | ||
prometheus | Server | Used for metrics. | ||
orb-service | Pipelines | Handles communication between orb registry and config. | ||
output-processor | Execution | Receives job output and status updates and writes them to MongoDB. Also provides an API to running jobs to access caches, workspaces, store caches, workspaces, artifacts, & test results. | ||
permissions-service | App Core | Provides the CircleCI permissions interface. | Workflows will fail to start and some REST API calls may fail, causing 500 errors in the UI. | |
scheduler | Execution | Runs tasks sent to it. Works with Nomad server. | No jobs will be sent to Nomad. The run queue will increase in size, but there should be no meaningful loss of data. | |
slanger | server | Provides real-time events to the CircleCI app. | Live UI updates will stop, but hard refreshes will still work. | |
test-results | Execution | Parses test result files and stores data. | There will be no test failure or timing data for jobs, but this will be back-filled once the service is restarted. | |
vm-gc | Compute Management | Periodically checks for stale machine and remote Docker instances and requests that vm-service remove them. | Old vm-service instances might not be destroyed until this service is restarted. | |
vm-scaler | Machine | Periodically requests that vm-service provision more instances for running machine and remote Docker jobs. | VM instances for machine and Remote Docker might not be provisioned, causing you to run out of capacity to run jobs with these executors. | Different overlay for EKS versus GKE. |
vm-service | Machine | Inventory of available vm-service instances, and provisioning of new instances. | Jobs that use machine or remote Docker will fail. | |
workflows-conductor-event-consumer | Pipelines | Takes in information from VCS to kick off pipelines. | New Pipelines will not be kicked off when there are changes in the VCS. | |
workflows-conductor-grpc-handler | Pipelines | Helps translate the information through gRPC. | ||
web-ui-* | Frontend | Micro Front End (MFE) services used to render the frontend web application GUI. | The respective services page will fail to load. Example: A web-ui-server-admin failure means the server Admin page will fail to load. | The MFEs are used to render the web application located at app.<my domain here> |
Platforms
CircleCI server is designed to deploy within a Kubernetes cluster. Virtual machine service (VM Service) is able to leverage unique EKS or GKE offerings to dynamically create VM images.
If installing outside of EKS or GKE, additional work is required to access some of the same machine build features. Setting up CircleCI runners gives you access to the same feature set as VM service across a much wider range of OSs and machine types (MacOS and much more).
We do our best to support a wide range of platforms for installation. We use environment-agnostic solutions wherever possible. However, we do not test all platforms and options. For that reason, we provide a list of tested environments, which we will continue to expand. We will be adding OpenShift to our list of regularly tested and supported platforms.
| Environment | Status | Notes |
|---|---|---|
EKS | Tested | |
GKE | Tested | |
Azure | Untested | Should work with Minio Azure gateway and Runner. |
Digital Ocean | Untested | Should work with Minio Digital Ocean gateway and Runner. |
OpenShift | Untested | Known to not work. |
Rancher | Untested | Should work with Minio and Runner. |
What to read next
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.
