celld is an alpha. The current release has these operational limits. See Cloudflare compatibility for the supported services, APIs, and Wrangler configuration.
- A fleet runs one application. celld has no account service, multi-tenant scheduler, or managed ingress.
- A fleet stores its durable state in an S3-compatible bucket, a Google Cloud
Storage bucket, or an Azure Blob Storage container. The
celld devcommand instead uses a local SQLite object store. A regular node or an operator subcommand cannot select this local backend. - A node does not rebalance the existing cells when it joins a fleet. Traffic assigns an unowned or released cell to a node with capacity.
- celld does not terminate TLS. Terminate public TLS at an ingress proxy, and put the internal listener on a private network or an encrypted overlay.
- Peer traffic crosses the internal network as plaintext HTTP. The fleet HMAC authenticates tunnel establishment and control requests, and it does not encrypt application data on the wire. The network layer must provide the confidentiality.
- The fleet bucket controls the fleet. Give its credentials access to one fleet only. See Security.
- celld supports different credential methods for each object storage provider. See Configure object storage for the available methods and their precedence.
- Azure identity support is limited to the public Azure cloud. A managed identity from Azure App Service or Azure Container Apps does not work. Use a workload identity or a storage account key on these platforms.
- An outbound Durable Object WebSocket keeps its cell resident. The connection closes if the cell moves to another node, so the application must store the connection intent and reconnect.
- A node limits the cells and outbound WebSockets that can remain resident.
- The installer supplies binaries for Linux x86-64, Linux ARM64, and Apple Silicon. Windows is not supported.