---
title: "Custom labels, annotations, and fields"
slug: "custom-labels"
tags: ["annotations", "labels"]
updated: 2024-04-26T07:23:36Z
published: 2024-04-26T07:23:36Z
---

> ## Documentation Index
> Fetch the complete documentation index at: https://traceabledocs.document360.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom labels, annotations, and fields

The option to use custom or existing label is available in Traceable agent 1.13.2 and later. If you are using a Helm chart or Terraform template to install the Traceable agent, you have the option to use a custom or existing namespace, pod labels, annotations, or field values. The topic provides a few examples of how to use label selectors, field selectors, annotations, and so on.

---

## Before you begin

Make sure that you have an understanding of:

- Labels and Selectors
- Field Selectors
- Understand the equality-based and set-based requirements and other label operators, like, `in`, `notin`, and so on.

---

## Examples

The section provides a few examples of using selectors and annotations.

### Example 1 - Label selector

Following is an example of a label selector:

```actionscript
app in (istio,ambassador,hackgoapp),service_app
```

In the above example, a pod will match if the app label is one of the three (istio, ambassador, hackgoapp) in the array and also contains a label key `service_app`.

### Example 2 - Field selector

Following is an example of a field selector:

```actionscript
metadata.namespace=traceable
```

In the above example, a pod will match if it is in the traceable namespace. In line with Kubernetes API, only a subset of fields are allowed for selection:

- `metadata.name`
- `metadata.namespace`
- `spec.nodeName`
- `spec.restartPolicy`
- `spec.scheduleName`
- `spec.serviceAccountName`

### Example 3 - Labels and annotations

If you have a deployment YAML, then for labels and annotations the fields are considered for matching are under spec.template.metadata, for example, as shown in the YAML below.

```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: hackgoapp
  namespace: hackgoapp
  labels:
    app: hackgoapp
spec:
  replicas: 1
  selector:
    matchLabels:
      app: hackgoapp
  template:
    metadata:
      labels: # This
        app: hackgoapp
      annotations: # And this
        foo: bar
    spec:
      containers:
      #
```

### Example 4

The following example shows the proxy injectee. Currently the following four are supported:

- Proxy
- Java
- Traceable module extension (tme)
- Mirror

```yaml
# Snippet from sample helm values.yaml
# -------------------------------
#
# inject if the pod meets any of the characteristics below. (i.e OR)
# - it contains the labels app=nginxapp, service_app=true and foo=baz AND
#     it's in the namespace traceable and restartPolicy is set to Always
# OR
# - it contains the label injector=hackgoapp
# OR
# - it contains the annotation app.kubernetes.io/name=myapp
injector:
  proxy:
    matchSelectors:
      - label_selectors:
          - "app=nginxapp,service_app=true"
          - "foo=baz"
        field_selectors:
          - "metadata.namespace=traceable,spec.restartPolicy=Always"
      - label_selectors:
          - "injector=hackgoapp"
      - annotation_selectors:
          - "app.kubernetes.io/name=myapp"
```

### Example 5 - Custom label for DaemonSet mirroring

The following example shows custom label for DaemonSet mirroring. The example:

- Captures mirroring traffic for namespace hackgoapp
- Captures egress traffic for the foo app in hackgoapp namespace

```actionscript
daemonSetMirroring:
  matchSelectors: 
    - field_selectors:
      - "metadata.namespace=hackgoapp"
  matchSelectorsEgress:
    - field_selectors:
      - "app=foo"
```

---

## Common Use Cases

### Injecting all pods in a namespace

Injecting a pod in a specific namespace is a common use case. For example, to inject a proxy into all the deployments in the namespace `hackgoapp`.

```yaml
injector:
  proxy:
    matchSelectors:
      - field_selectors:
          - "metadata.namespace=hackgoapp"
```

### Injecting all pods in namespace except some

You can inject pods in a particular namespace except one. For example, if you want to inject all pods in a namespace `hackgoapp` with the exception of those whose app label value is `foo` or `baz`, then you can have a YAML like shown below:

```yaml
injector:
  proxy:
    matchSelectors:
      - field_selectors:
          - "metadata.namespace=hackgoapp"
        label_selectors:
          - "app notin (foo,baz)"
```