# TIL: kubectl JSONPath: Extract Exactly What You Need
Stop piping kubectl output to grep, awk, and sed. JSONPath can get you exactly what you need in one command.
The Basic Pattern
bash
kubectl get <resource> -o jsonpath='{<jsonpath-expression>}'Simple Examples
Get Pod IPs
Instead of:
Do:
Get Pod Names Only
bash
kubectl get pods -o jsonpath='{.items[*].metadata.name}'Get Pod Name + IP
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kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.podIP}{"\n"}{end}'Output:
Real-World Use Cases
1. Find All Container Images
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kubectl get pods -o jsonpath='{.items[*].spec.containers[*].image}' | tr ' ' '\n' | sort -u2. Get Pods Not Running
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kubectl get pods -o jsonpath='{range .items[?(@.status.phase!="Running")]}{.metadata.name}{"\t"}{.status.phase}{"\n"}{end}'3. Find Pods Using Most Memory
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kubectl top pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.usage.memory}{"\n"}{end}' | sort -k2 -h4. Get All Node Capacities
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kubectl get nodes -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.capacity.cpu}{" CPU\t"}{.status.capacity.memory}{" RAM\n"}{end}'5. Find Secrets in a Namespace
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kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.volumes[?(@.secret)].secret.secretName}{"\n"}{end}'6. Get All Services and Their Type
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kubectl get svc -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.type}{"\n"}{end}'JSONPath Syntax Cheat Sheet
| Pattern | Description | Example |
|---|---|---|
.items[*] | All items | Get all pods |
.items[0] | First item | Get first pod |
.items[0:3] | First 3 items | Get first 3 pods |
.items[-1] | Last item | Get last pod |
.items[?(@.field=="value")] | Filter | Pods where phase=Running |
{range .items[*]}...{end} | Loop | Iterate over items |
{"\n"} | Newline | Format output |
{"\t"} | Tab | Format output |
Advanced Filtering
Pods with Specific Label
bash
kubectl get pods -l app=nginx -o jsonpath='{.items[*].metadata.name}'Pods in Running State
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kubectl get pods -o jsonpath='{.items[?(@.status.phase=="Running")].metadata.name}'Containers in Waiting State
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kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.containerStatuses[?(@.state.waiting)].name}{"\n"}{end}'Pods with Restart Count > 0
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kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.containerStatuses[0].restartCount}{"\n"}{end}' | awk '$2 > 0'Useful Aliases
Add to your ~/.bashrc or ~/.zshrc:
bash
# Get pod IPs
alias kip='kubectl get pods -o jsonpath='\''{range .items[*]}{.metadata.name}{"\t"}{.status.podIP}{"\n"}{end}'\'''Get images alias kimages='kubectl get pods -o jsonpath='\''{.items[*].spec.containers[*].image}'\'' | tr " " "\n" | sort -u'
Get pod with most restarts alias krestart='kubectl get pods -o jsonpath='\''{range .items[*]}{.metadata.name}{"\t"}{.status.containerStatuses[0].restartCount}{"\n"}{end}'\'' | sort -k2 -n -r | head -1'
Get not ready pods alias knotready='kubectl get pods -o jsonpath='\''{range .items[?(@.status.phase!="Running")]}{.metadata.name}{"\t"}{.status.phase}{"\n"}{end}'\''' ```
Custom Columns (Even Better)
Sometimes custom columns are cleaner than JSONPath:
bash
# Pod name, phase, and IP
kubectl get pods -o custom-columns=NAME:.metadata.name,PHASE:.status.phase,IP:.status.podIPNode name, CPU, and memory kubectl get nodes -o custom-columns=NAME:.metadata.name,CPU:.status.capacity.cpu,MEMORY:.status.capacity.memory
Services and their ClusterIP kubectl get svc -o custom-columns=NAME:.metadata.name,TYPE:.spec.type,CLUSTER-IP:.spec.clusterIP ```
Common Patterns I Use Daily
1. Quick Debug: Get All Pod Info
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kubectl get pod nginx-abc123 -o jsonpath='{range .spec.containers[*]}Name: {.name}{"\n"}Image: {.image}{"\n"}Ports: {.ports[*].containerPort}{"\n\n"}{end}'2. Get All Environment Variables
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kubectl get pod nginx-abc123 -o jsonpath='{range .spec.containers[*].env[*]}{.name}={.value}{"\n"}{end}'3. Find Pods on a Specific Node
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kubectl get pods --all-namespaces -o jsonpath='{range .items[?(@.spec.nodeName=="node-1")]}{.metadata.name}{"\t"}{.metadata.namespace}{"\n"}{end}'4. Get ConfigMaps Used by Pods
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kubectl get pods -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.volumes[?(@.configMap)].configMap.name}{"\n"}{end}'5. Network Policies Applied to Pods
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kubectl get netpol -o jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.spec.podSelector.matchLabels}{"\n"}{end}'The Power Move
Combine JSONPath with watch for live updates:
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watch -n 2 'kubectl get pods -o jsonpath='\''{range .items[*]}{.metadata.name}{"\t"}{.status.phase}{"\n"}{end}'\'''Debugging JSONPath
If your JSONPath isn't working, test it step by step:
bash
# Get full JSON first
kubectl get pod nginx-abc123 -o json | jq '.'Then build your JSONPath incrementally kubectl get pod nginx-abc123 -o jsonpath='{.metadata}' kubectl get pod nginx-abc123 -o jsonpath='{.metadata.name}' kubectl get pod nginx-abc123 -o jsonpath='{.status}' kubectl get pod nginx-abc123 -o jsonpath='{.status.phase}' ```
The Gotcha
JSONPath in kubectl has some quirks:
- **Filters must use
@**:.items[?(@.field=="value")]not.items[?(.field=="value")] - **Arrays need
[*]**:.items[*]not.items[] - Quotes matter: Use single quotes outside, double inside:
'{.items[?(@.name=="value")]}'
This has eliminated so much grep | awk | sed pipeline complexity from my daily kubectl commands. One-liner power!