kubectl-sql

kubectl-sql is a kubectl plugin that use SQL like language to query the Kubernetes cluster manager

• Install
• What can I do with it ?
• Alternatives

More docs

• kubectl-sql's query language
• More kubectl-sql examples
• Using the config file

Install

Using krew plugin manager to install:

# Available for linux-amd64
kubectl krew install sql
kubectl sql --help

Using Fedora Copr:

# Available for F41 and F42 (linux-amd64)
dnf copr enable yaacov/kubesql
dnf install kubectl-sql

From source:

# Clone code
git clone [email protected]:yaacov/kubectl-sql.git
cd kubectl-sql

# Build kubectl-sql
make

# Install into local machine PATH
sudo install ./kubectl-sql /usr/local/bin/

What can I do with it ?

kubectl-sql let you select Kubernetes resources based on the value of one or more resource fields, using human readable easy to use SQL like query language. It is also posible to find connected resources useing the join command.

More kubectl-sql examples

# Get pods in namespace "openshift-multus" that hase name containing "cni"
# Select the fields name, status.phase as phase, status.podIP as ip
kubectl-sql "select name, status.phase as phase, status.podIP as ip \
  from openshift-multus/pods \
  where name ~= 'cni' and (ip ~= '5$' or phase = 'Running')"
KIND: Pod	COUNT: 2
name                               	phase  	ip          	
multus-additional-cni-plugins-7kcsd	Running	10.130.10.85	
multus-additional-cni-plugins-kc8sz	Running	10.131.6.65 
...

# Get all persistant volume clames that are less then 20Gi, and output as json.
kubectl-sql -o json "select * from pvc where spec.resources.requests.storage < 20Gi"
...

# Display non running pods by nodes for all namespaces.
kubectl-sql "select * from nodes join pods on \
    nodes.status.addresses[1].address = pods.status.hostIP and not pods.phase ~= 'Running'" -A
...

# Filter replica sets with less ready-replicas then replicas"
kubectl-sql --all-namespaces "select * from rs where status.readyReplicas < status.replicas"

Output formats:

--output flag	Print format
table	Table
name	Names only
yaml	YAML
json	JSON

Alternatives

jq

jq is a lightweight and flexible command-line JSON processor. It is possible to pipe the kubectl command output into the jq command to create complicated searches ( Illustrated jq toturial )

https://stedolan.github.io/jq/manual/#select(boolean_expression)

kubectl --field-selector

Field selectors let you select Kubernetes resources based on the value of one or more resource fields. Here are some examples of field selector queries.

https://kubernetes.io/docs/concepts/overview/working-with-objects/field-selectors/