spring-projects/spring-boot · error · DockerConnectionException

Connection to the Docker daemon at '${host}' failed with err

Error message

Connection to the Docker daemon at '${host}' failed with error "${causeMessage}"; ensure the Docker daemon is running and accessible

What it means

Error "Connection to the Docker daemon at '${host}' failed with error "${causeMessage}"; ensure the Docker daemon is running and accessible" thrown in spring-projects/spring-boot.

Source

Thrown at buildpack/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/transport/HttpClientTransport.java:176

	}

	private Response execute(HttpUriRequest request) {
		try {
			beforeExecute(request);
			ClassicHttpResponse response = this.client.executeOpen(this.host, request, null);
			int statusCode = response.getCode();
			if (statusCode >= 400 && statusCode <= 500) {
				byte[] content = readContent(response);
				response.close();
				Errors errors = (statusCode != 500) ? deserializeErrors(content) : null;
				Message message = deserializeMessage(content);
				throw new DockerEngineException(this.host.toHostString(), request.getUri(), statusCode,
						response.getReasonPhrase(), errors, message, content);
			}
			return new HttpClientResponse(response);
		}
		catch (IOException | URISyntaxException ex) {
			throw new DockerConnectionException(this.host.toHostString(), ex);
		}
	}

	protected void beforeExecute(HttpRequest request) {
	}

	private byte @Nullable [] readContent(ClassicHttpResponse response) throws IOException {
		HttpEntity entity = response.getEntity();
		if (entity == null) {
			return null;
		}
		try (InputStream stream = entity.getContent()) {
			return (stream != null) ? stream.readAllBytes() : null;
		}
	}

	private @Nullable Errors deserializeErrors(byte @Nullable [] content) {
		if (content == null) {

View on GitHub (pinned to 5b2dbdbb8b)

When it happens

Trigger: Thrown at buildpack/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/transport/HttpClientTransport.java:176 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of spring-projects/spring-boot@5b2dbdbb8b (2026-08-04). Data as JSON: /data/errors/ae73fff2c3a4b2b8.json. Report an issue: GitHub.