zed-industries/zed · error · anyhow::Error

Failed to create iopub connection: {}. Is `ipykernel` instal

Error message

Failed to create iopub connection: {}. Is `ipykernel` installed in the remote environment? Try running `pip install ipykernel` on the remote host.

What it means

Creating the iopub client connection to the remote kernel failed after retries, almost always because ipykernel is missing in the remote environment; the message tells the user to pip install ipykernel on the remote host.

Source

Thrown at crates/repl/src/kernels/ssh_kernel.rs:227

            let connection_info_struct: runtimelib::ConnectionInfo =
                serde_json::from_value(local_connection_info)?;
            let session_id = uuid::Uuid::new_v4().to_string();

            let output_socket = {
                let max_retries = 5;
                let mut retry = 0;
                loop {
                    match runtimelib::create_client_iopub_connection(
                        &connection_info_struct,
                        "",
                        &session_id,
                    )
                    .await
                    {
                        Ok(socket) => break socket,
                        Err(err) => {
                            if retry >= max_retries {
                                anyhow::bail!(
                                    "Failed to create iopub connection: {}. Is `ipykernel` installed in the remote environment? Try running `pip install ipykernel` on the remote host.",
                                    err
                                );
                            }
                            log::debug!(
                                "Retrying iopub connection (attempt {}/{})",
                                retry + 1,
                                max_retries
                            );
                            cx.background_executor()
                                .timer(std::time::Duration::from_millis(200 << retry))
                                .await;
                            retry += 1;
                        }
                    }
                }
            };

View on GitHub (pinned to f4178619ac)

Solutions

1. Run `pip install ipykernel` in the remote environment as the message suggests
2. Verify the remote kernel process is fully started before connecting
3. Retry; the connection retries up to 5 times internally before failing

When it happens

Trigger: Thrown at crates/repl/src/kernels/ssh_kernel.rs:227 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of zed-industries/zed@f4178619ac (2026-08-20). Data as JSON: /api/errors/0a15733fbb1c002d. Report an issue: GitHub.