# 4. YAML Configuration File
### Introduction
* Config File is written in YAML Format
* Config File should be stored with the code inside SCM
***
### 3 Parts of K8 Config File
1. Metadata
2. Specification
3. Status (Auto Generated & Added by K8)
* K8 Gets Status from etcd
***
### Template
* The specified **kind** has its own *metadata* and *spec*
* Pod has also a section of its own which contains its own configuration
#### Labels & Connectors
* *Metadata* section contain the labels
* *Spec* section contains the selectors
**Connecting Deployment to Pods**
* Deployment looks which pods belong to it using labels (key value pairs)
* The label is matched by the selector
**Connecting Services to Deployments**
* Similar concept as connecting deployment to pods
#### Ports in Service & Pods
* Service listens on port and forwards the request to target port which must be of a pod
### Minimal Deployment File
```yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx:1.16
ports:
- containerPort: 8080
```
***
### Minimal Service File
```yaml
apiVersion: v1
kind: Service
metadata:
name: nginx-service
spec:
selector:
app: nginx
ports:
- protocol: TCP
port: 80
targetPort: 8080
```
***
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