mcp-server-kubernetes

Instructions

Implementation Reference

• src/tools/kubectl-logs.ts:72-274 (handler)

  Main handler function for the 'kubectl_logs' tool. Executes kubectl logs commands for pods, deployments, jobs, and cronjobs, supporting various options like tail, since, container selection, and label selectors. Handles multi-pod scenarios by fetching logs from all matching pods.
  export async function kubectlLogs( k8sManager: KubernetesManager, input: { resourceType: string; name: string; namespace: string; container?: string; tail?: number; since?: string; sinceTime?: string; timestamps?: boolean; previous?: boolean; follow?: boolean; labelSelector?: string; context?: string; } ) { try { const resourceType = input.resourceType.toLowerCase(); const name = input.name; const namespace = input.namespace || "default"; const context = input.context || ""; const command = "kubectl"; // Handle different resource types if (resourceType === "pod") { // Direct pod logs let args = ["-n", namespace, "logs", name]; // If container is specified, add it if (input.container) { args.push(`-c`, input.container); } // Add options args = addLogOptions(args, input); // Add context if provided if (context) { args.push("--context", context); } // Execute the command try { const result = execFileSync(command, args, { encoding: "utf8", maxBuffer: getSpawnMaxBuffer(), env: { ...process.env, KUBECONFIG: process.env.KUBECONFIG }, }); return formatLogOutput(name, result); } catch (error: any) { return handleCommandError(error, `pod ${name}`); } } else if ( resourceType === "deployment" || resourceType === "job" || resourceType === "cronjob" ) { // For deployments, jobs and cronjobs we need to find the pods first let selectorArgs; if (resourceType === "deployment") { selectorArgs = [ "-n", namespace, "get", "deployment", name, "-o", "jsonpath='{.spec.selector.matchLabels}'", ]; } else if (resourceType === "job") { // For jobs, we use the job-name label return getLabelSelectorLogs(`job-name=${name}`, namespace, input); } else if (resourceType === "cronjob") { // For cronjobs, it's more complex - need to find the job first const jobsArgs = [ "-n", namespace, "get", "jobs", "--selector=job-name=" + name, "-o", "jsonpath='{.items[*].metadata.name}'", ]; try { const jobs = execFileSync(command, jobsArgs, { encoding: "utf8", maxBuffer: getSpawnMaxBuffer(), env: { ...process.env, KUBECONFIG: process.env.KUBECONFIG }, }) .trim() .split(" "); if (jobs.length === 0 || (jobs.length === 1 && jobs[0] === "")) { return { content: [ { type: "text", text: JSON.stringify( { message: `No jobs found for cronjob ${name} in namespace ${namespace}`, }, null, 2 ), }, ], }; } // Get logs for all jobs const allJobLogs: Record<string, any> = {}; for (const job of jobs) { // Get logs for pods from this job const result = await getLabelSelectorLogs( `job-name=${job}`, namespace, input ); const jobLog = JSON.parse(result.content[0].text); allJobLogs[job] = jobLog.logs; } return { content: [ { type: "text", text: JSON.stringify( { cronjob: name, namespace: namespace, jobs: allJobLogs, }, null, 2 ), }, ], }; } catch (error: any) { return handleCommandError(error, `cronjob ${name}`); } } try { if (resourceType === "deployment") { // Get the deployment's selector if (!selectorArgs) { throw new Error("Selector command is undefined"); } const selectorJson = execFileSync(command, selectorArgs, { encoding: "utf8", maxBuffer: getSpawnMaxBuffer(), env: { ...process.env, KUBECONFIG: process.env.KUBECONFIG }, }).trim(); const selector = JSON.parse(selectorJson.replace(/'/g, '"')); // Convert to label selector format const labelSelector = Object.entries(selector) .map(([key, value]) => `${key}=${value}`) .join(","); return getLabelSelectorLogs(labelSelector, namespace, input); } // For jobs and cronjobs, the logic is handled above return { content: [ { type: "text", text: JSON.stringify( { error: `Unexpected resource type: ${resourceType}`, }, null, 2 ), }, ], isError: true, }; } catch (error: any) { return handleCommandError(error, `${resourceType} ${name}`); } } else if (input.labelSelector) { // Handle logs by label selector return getLabelSelectorLogs(input.labelSelector, namespace, input); } else { throw new McpError( ErrorCode.InvalidRequest, `Unsupported resource type: ${resourceType}` ); } } catch (error: any) { if (error instanceof McpError) throw error; throw new McpError( ErrorCode.InternalError, `Failed to get logs: ${error.message}` ); } }
• src/tools/kubectl-logs.ts:10-70 (schema)

  Input schema and metadata for the kubectl_logs tool, defining required and optional parameters.
  export const kubectlLogsSchema = { name: "kubectl_logs", description: "Get logs from Kubernetes resources like pods, deployments, or jobs", annotations: { readOnlyHint: true, }, inputSchema: { type: "object", properties: { resourceType: { type: "string", enum: ["pod", "deployment", "job", "cronjob"], description: "Type of resource to get logs from", }, name: { type: "string", description: "Name of the resource", }, namespace: namespaceParameter, container: { type: "string", description: "Container name (required when pod has multiple containers)", }, tail: { type: "number", description: "Number of lines to show from end of logs", }, since: { type: "string", description: "Show logs since relative time (e.g. '5s', '2m', '3h')", }, sinceTime: { type: "string", description: "Show logs since absolute time (RFC3339)", }, timestamps: { type: "boolean", description: "Include timestamps in logs", default: false, }, previous: { type: "boolean", description: "Include logs from previously terminated containers", default: false, }, follow: { type: "boolean", description: "Follow logs output (not recommended, may cause timeouts)", default: false, }, labelSelector: { type: "string", description: "Filter resources by label selector", }, context: contextParameter, }, required: ["resourceType", "name", "namespace"], }, } as const;
• src/index.ts:292-310 (registration)

  Registration and dispatch logic in the main CallToolRequestSchema handler that routes 'kubectl_logs' tool calls to the kubectlLogs function.
  if (name === "kubectl_logs") { return await kubectlLogs( k8sManager, input as { resourceType: string; name: string; namespace: string; container?: string; tail?: number; since?: string; sinceTime?: string; timestamps?: boolean; previous?: boolean; follow?: boolean; labelSelector?: string; context?: string; } ); }
• src/index.ts:100-140 (registration)

  Tool schema is included in the allTools array, which is used by ListToolsRequestSchema to expose the tool.
  const allTools = [ // Core operation tools cleanupSchema, // Unified kubectl-style tools - these replace many specific tools kubectlGetSchema, kubectlDescribeSchema, kubectlApplySchema, kubectlDeleteSchema, kubectlCreateSchema, kubectlLogsSchema, kubectlScaleSchema, kubectlPatchSchema, kubectlRolloutSchema, // Kubernetes context management kubectlContextSchema, // Special operations that aren't covered by simple kubectl commands explainResourceSchema, // Helm operations installHelmChartSchema, upgradeHelmChartSchema, uninstallHelmChartSchema, nodeManagementSchema, // Port forwarding PortForwardSchema, StopPortForwardSchema, execInPodSchema, // API resource operations listApiResourcesSchema, // Generic kubectl command kubectlGenericSchema, // Ping utility pingSchema, ];
• src/tools/kubectl-logs.ts:311-401 (helper)

  Helper function to retrieve logs from multiple pods matching a label selector, used for deployments, jobs, etc.
  async function getLabelSelectorLogs( labelSelector: string, namespace: string, input: any ): Promise<{ content: Array<{ type: string; text: string }> }> { try { const command = "kubectl"; // First, find all pods matching the label selector const podsArgs = [ "-n", namespace, "get", "pods", `--selector=${labelSelector}`, "-o", "jsonpath='{.items[*].metadata.name}'", ]; const pods = execFileSync(command, podsArgs, { encoding: "utf8", maxBuffer: getSpawnMaxBuffer(), env: { ...process.env, KUBECONFIG: process.env.KUBECONFIG }, }) .trim() .split(" "); if (pods.length === 0 || (pods.length === 1 && pods[0] === "")) { return { content: [ { type: "text", text: JSON.stringify( { message: `No pods found with label selector "${labelSelector}" in namespace ${namespace}`, }, null, 2 ), }, ], }; } // Get logs for each pod const logsMap: Record<string, string> = {}; for (const pod of pods) { // Skip empty pod names if (!pod) continue; let podArgs = ["-n", namespace, "logs", pod]; // Add container if specified if (input.container) { podArgs.push(`-c`, input.container); } // Add other options podArgs = addLogOptions(podArgs, input); try { const logs = execFileSync(command, podArgs, { encoding: "utf8", maxBuffer: getSpawnMaxBuffer(), env: { ...process.env, KUBECONFIG: process.env.KUBECONFIG }, }); logsMap[pod] = logs; } catch (error: any) { logsMap[pod] = `Error: ${error.message}`; } } return { content: [ { type: "text", text: JSON.stringify( { selector: labelSelector, namespace: namespace, logs: logsMap, }, null, 2 ), }, ], }; } catch (error: any) { return handleCommandError(error, `pods with selector "${labelSelector}"`); } }