Garrett Delfosse
54d650ea79
When the control plane connection drops and reconnects, a new `tunnelUpdater` is created with empty workspace state. This causes the in-memory DNS resolver to lose all host records, breaking `.coder` name resolution until the server sends a fresh workspace snapshot. If the API is unreachable (e.g., the route goes through a VPN that is also reconnecting), the snapshot never arrives and DNS stays broken indefinitely — requiring a full Coder Desktop restart. Fix: carry workspace state from the previous `tunnelUpdater` to the new one on reconnect, and immediately re-apply DNS hosts so the resolver stays populated during the reconnection window. Fixes https://linear.app/codercom/issue/PLAT-110 <details><summary>Investigation & decision log</summary> ### Root cause analysis Customer diagnostic data from Roblox (March 31) showed: - NRPT rule present (`.coder` → `fd60:627a:a42b::53`) — routing is correct - DNS resolver returns NXDOMAIN for everything including the sentinel `is.coder--connect--enabled--right--now.coder` — resolver is running but has zero host records - Coder Connect UI shows "connected" — the WireGuard data plane is up The resolver is empty because `TunnelAllWorkspaceUpdatesController.New()` creates a fresh `tunnelUpdater` with `workspaces: make(map[uuid.UUID]*Workspace)` (empty). The previous updater's workspace data is discarded. If the server's workspace snapshot is delayed or the API is unreachable, the resolver has no records to serve. This is compounded by GlobalProtect VPN reconnects: the Coder API is behind the VPN, so when GP reconnects, the API route is temporarily lost and the snapshot can't arrive. ### What this PR changes - `TunnelAllWorkspaceUpdatesController.New()` now clones workspace state from the previous updater before creating the new one - Immediately re-applies DNS hosts with the inherited state (log: `re-applying DNS hosts from previous session`) - When the server's snapshot arrives, it replaces the inherited data normally - If `SetDNSHosts` fails during re-apply, it's logged as a warning and not fatal — the recvLoop will program DNS when the snapshot arrives ### What this PR does NOT fix (future work) - **Tunnel binary restart**: when the tunnel process itself is killed and relaunched, all in-memory state is lost. A DNS host cache on disk would be needed for this case. - **NRPT rule cleanup on startup**: the Tailscale fork's `nrptRuleDatabase` constructor unconditionally deletes all NRPT rules on engine creation. Deferring cleanup to the first successful `SetDNS` call would reduce the DNS gap. - **Hosts file retry**: the `setHosts()` retry in the Tailscale fork (5×10ms) is too short for environments where endpoint security locks the file. These are tracked as follow-up items in the `coder/tailscale` fork. </details> > 🤖 Generated by Coder Agents
Coder enables organizations to set up development environments in their public or private cloud infrastructure. Cloud development environments are defined with Terraform, connected through a secure high-speed Wireguard® tunnel, and automatically shut down when not used to save on costs. Coder gives engineering teams the flexibility to use the cloud for workloads most beneficial to them.
- Define cloud development environments in Terraform
- EC2 VMs, Kubernetes Pods, Docker Containers, etc.
- Automatically shutdown idle resources to save on costs
- Onboard developers in seconds instead of days
Quickstart
The most convenient way to try Coder is to install it on your local machine and experiment with provisioning cloud development environments using Docker (works on Linux, macOS, and Windows).
# First, install Coder
curl -L https://coder.com/install.sh | sh
# Start the Coder server (caches data in ~/.cache/coder)
coder server
# Navigate to http://localhost:3000 to create your initial user,
# create a Docker template and provision a workspace
Install
The easiest way to install Coder is to use our
install script for Linux
and macOS. For Windows, use the latest ..._installer.exe file from GitHub
Releases.
curl -L https://coder.com/install.sh | sh
You can run the install script with --dry-run to see the commands that will be used to install without executing them. Run the install script with --help for additional flags.
See install for additional methods.
Once installed, you can start a production deployment with a single command:
# Automatically sets up an external access URL on *.try.coder.app
coder server
# Requires a PostgreSQL instance (version 13 or higher) and external access URL
coder server --postgres-url <url> --access-url <url>
Use coder --help to get a list of flags and environment variables. Use our install guides for a complete walkthrough.
Documentation
Browse our docs here or visit a specific section below:
- Templates: Templates are written in Terraform and describe the infrastructure for workspaces
- Workspaces: Workspaces contain the IDEs, dependencies, and configuration information needed for software development
- IDEs: Connect your existing editor to a workspace
- Administration: Learn how to operate Coder
- Premium: Learn about our paid features built for large teams
Support
Feel free to open an issue if you have questions, run into bugs, or have a feature request.
Join our Discord to provide feedback on in-progress features and chat with the community using Coder!
Integrations
We are always working on new integrations. Please feel free to open an issue and ask for an integration. Contributions are welcome in any official or community repositories.
Official
- VS Code Extension: Open any Coder workspace in VS Code with a single click
- JetBrains Toolbox Plugin: Open any Coder workspace from JetBrains Toolbox with a single click
- JetBrains Gateway Plugin: Open any Coder workspace in JetBrains Gateway with a single click
- Dev Container Builder: Build development environments using
devcontainer.jsonon Docker, Kubernetes, and OpenShift - Coder Registry: Build and extend development environments with common use-cases
- Kubernetes Log Stream: Stream Kubernetes Pod events to the Coder startup logs
- Self-Hosted VS Code Extension Marketplace: A private extension marketplace that works in restricted or airgapped networks integrating with code-server.
- Setup Coder: An action to setup coder CLI in GitHub workflows.
Community
- Provision Coder with Terraform: Provision Coder on Google GKE, Azure AKS, AWS EKS, DigitalOcean DOKS, IBMCloud K8s, OVHCloud K8s, and Scaleway K8s Kapsule with Terraform
- Coder Template GitHub Action: A GitHub Action that updates Coder templates
Contributing
We are always happy to see new contributors to Coder. If you are new to the Coder codebase, we have a guide on how to get started. We'd love to see your contributions!
Hiring
Apply here if you're interested in joining our team.