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AWS AmazonECS documentation change

Service: AmazonECS · 2025-10-25 · Documentation low

File: AmazonECS/latest/developerguide/troubleshooting-managed-instances-complete.md

Summary

Added new section for agent disconnect troubleshooting including IAM/SG checks, service restarts, and deregistration commands

Security assessment

Includes security-adjacent troubleshooting steps (IAM role verification, security group checks) but does not fix vulnerabilities - documents security-related operational practices

Diff

diff --git a/AmazonECS/latest/developerguide/troubleshooting-managed-instances-complete.md b/AmazonECS/latest/developerguide/troubleshooting-managed-instances-complete.md
index 0bc299b4b..107d0776e 100644
--- a//AmazonECS/latest/developerguide/troubleshooting-managed-instances-complete.md
+++ b//AmazonECS/latest/developerguide/troubleshooting-managed-instances-complete.md
@@ -15 +15 @@ Before troubleshooting Amazon ECS Managed Instances, ensure that you have the fo
-  * The AWS CLI installed and configured with appropriate permissions
+  * The AWS CLI is installed and configured with appropriate permissions
@@ -32 +32 @@ You can view these Amazon ECS log files in Amazon ECS Managed Instances by conne
-**Deploy Debug Container with privileges and Linux capabilities as Amazon ECS task:**
+**Deploy a debug container with privileges and Linux capabilities as an Amazon ECS task:**
@@ -70,3 +69,0 @@ Create a task definition using a CLI JSON file called `node-debugger.json`.
-            "capabilities": {
-              "add": ["NET_ADMIN", "SYS_ADMIN", "BPF"]
-            },
@@ -129 +126 @@ Connect to the container. Run the following command.
-**Check Amazon ECS Agent Logs:**
+**Check the Amazon ECS agent logs:**
@@ -150 +147 @@ In the interactive session of the container, run the following commands:
-**Check Agent Metrics:**
+**Check agent metrics:**
@@ -196 +193 @@ Run the following commands to diagnose task placement issues and gather informat
-**System Service Monitoring:**
+**System service monitoring:**
@@ -233 +230 @@ The following are synptoms of networking issues:
-**Network Connectivity Tests:**
+**Network connectivity tests:**
@@ -268 +265 @@ Run commands to monitory the resources and container limits.
-**Resource Monitoring:**
+**Resource monitoring:**
@@ -285,0 +283,55 @@ Run commands to monitory the resources and container limits.
+### Container instance agent disconnect issue
+
+The following are symptoms of container instance agent disconnect issues:
+
+  * Container instances showing as disconnected in the Amazon ECS console
+
+  * Tasks failing to be placed on specific instances
+
+  * Agent registration failures in logs
+
+
+
+
+#### Diagnostic steps
+
+If there is an existing privilege task running on the host that ECS Exec can access, run the following commands to diagnose agent connectivity issues:
+    
+    
+    # check service status 
+    nsenter -t 1 -m -p systemctl restart ecs 
+    nsenter -t 1 -m -p systemctl restart containerd 
+    
+    # restart stopped services 
+    nsenter -t 1 -m -p systemctl restart ecs 
+    nsenter -t 1 -m -p systemctl restart containerd
+
+Otherwise, force deregister the Amazon ECS Managed Instances. Run the following command:
+    
+    
+    # list ECS Managed Instance container
+    aws ecs list-container-instances --cluster managed-instances-cluster --query 'containerInstanceArns' --output text
+    
+    # deregister the specific container instance
+    aws ecs deregister-container-instance \
+        --cluster $ECS_CLUSTER_NAME \
+        --container-instance container-instance-arn \
+        --force
+
+#### Resolution
+
+To resolve agent disconnect issues, follow these steps:
+
+  * Verify IAM role permissions for the container instance
+
+  * Check security group rules allow outbound HTTPS traffic to ECS endpoints
+
+  * Ensure network connectivity to AWS services
+
+  * Restart the ECS agent service if necessary: `nsenter -t 1 -m -p systemctl restart ecs`
+
+  * Verify the ECS_CLUSTER configuration in /etc/ecs/ecs.config matches your cluster name
+
+
+
+