Ignore the NotReady state of the sidecar container to prevent affecting the status of the pod - Elastic Container Instance

Elastic Container Instance (ECI) does not support Kubernetes DaemonSets on virtual nodes. A common workaround is to inject a sidecar container into an ECI-based pod to replicate DaemonSet behavior — for example, to run a log collector or monitoring agent. By default, if that sidecar enters a NotReady state, the entire pod is marked NotReady, which blocks traffic to otherwise-healthy application containers. To decouple sidecar readiness from pod readiness, set the ECI_CONTAINER_IGNORE_READY environment variable on the sidecar container.

How it works

Pod readiness is determined by two conditions in status.conditions:

Condition	Meaning
`ContainersReady`	All containers in the pod are ready.
`Ready`	The pod can serve requests (used by Services for load balancing).

Normally, if any container is NotReady, both conditions are False. When you set ECI_CONTAINER_IGNORE_READY: "true" on a container, ECI excludes that container from readiness evaluation. Both ContainersReady and Ready can reach True even while that container remains NotReady.

Prerequisites

Before you begin, make sure you have:

An ACK Serverless cluster with ECI-based virtual nodes
kubectl configured to connect to your cluster

Ignore the NotReady state of a sidecar container

Create a Deployment manifest. The following example creates a Deployment with two containers: c1 runs normally, and c2 has no startup command and cannot enter the Ready state. ECI_CONTAINER_IGNORE_READY is set on c2 to exclude it from readiness evaluation.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test-ignore
  labels:
    app: test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: test
  template:
    metadata:
      labels:
        app: test
    spec:
      containers:
      - name: c1
        image: registry.cn-shanghai.aliyuncs.com/eci_open/perl:5
        command: ["/bin/sh", "-c", "sleep 999"]
      - name: c2
        image: registry.cn-shanghai.aliyuncs.com/eci_open/centos:7
        env:
        - name: ECI_CONTAINER_IGNORE_READY
          value: "true"

Apply the manifest.
```
kubectl apply -f test-ignore.yaml
```

Verify the configuration

After the pod starts, check its readiness conditions to confirm that the NotReady state of c2 is being ignored.

Retrieve the pod status.
```
kubectl get pod <pod-name> -o yaml
```
In the output, locate the status.conditions section. With ECI_CONTAINER_IGNORE_READY set correctly, both conditions show True:
```
status:
  conditions:
  - type: ContainersReady
    status: "True"
  - type: Ready
    status: "True"
```

The following screenshot shows an example of the expected output.