PI4 Stories¶
Raspberry Pi 4 cluster Series - Spin up graphite and temperature2celsius pods¶
Graphite is an enterprise-ready monitoring tool that runs equally well on cheap hardware or Cloud infrastructure. Teams use Graphite to track the performance of their websites, applications, business services, and networked servers. It marked the start of a new generation of monitoring tools, making it easier than ever to store, retrieve, share, and visualize time-series data. Info copied from web-site graphiteapp.org.
Spin up graphite pod¶
To start we need the sources to build of graphite pod, therefore, clone our pi4-graphite github repository [1]:
git clone https://github.com/gdha/pi4-graphite.git
You will find in the pi4-graphite directory a Dockerfile which will be used to create a new container image:
To build the docker image on your Pi4 system execute the following command:
$ ./build.sh v1.2
Login Succeeded
Building graphite:v1.2
Sending build context to Docker daemon 137.2kB
Step 1/11 : FROM graphiteapp/graphite-statsd:1.1.10-4
1.1.10-4: Pulling from graphiteapp/graphite-statsd
9981e73032c8: Pull complete
de219cb0be19: Pull complete
a152a03e3913: Pull complete
1e02b3e21032: Pull complete
fb7d8007a803: Pull complete
Digest: sha256:fb9eb6fdd8f6073dd4ff1acd2169b693d4633045017701713651befbc62fe9f5
Status: Downloaded newer image for graphiteapp/graphite-statsd:1.1.10-4
...
Successfully built afb29746df49
Successfully tagged ghcr.io/gdha/graphite:v1.2
Pushing graphite:v1.2 to GitHub Docker Container registry
To start the graphite pod on our kubernetes cluster do the following:
$ cd kubernetes
$ kubectl apply -f ./graphite-namespace.yaml
namespace/graphite created
$ kubectl apply -f ./graphite-secret.yaml
secret/graphite created
$ kubectl apply -f ./ghcr-secret.yaml secret/dockerconfigjson-github-com
created
$ kubectl apply -f ./persistentvolumeclaim-graphite.yaml persistentvolumeclaim/graphite
created
$ kubectl apply -f ./statefulset_graphite.yaml statefulset.apps/graphite
created
$ kubectl apply -f ./service_graphite.yaml service/graphite-svc
created
Open a browser with URL http://n1:30080 to see the result of the tests:
Deploy temperature2celsius pods¶
The purpose of this pod is to demonstrate that we can send information to our graphite application. We choose to send the temperatire in Celsius once a minute.
Start with cloning our pi4-temperature2graphite github repository [2]:
git clone https://github.com/gdha/pi4-temperature2graphite.git
cd pi4-temperature2graphite
The Dockerfile content is:
# Dockerfile to create the container used to send the temperature of the RPI4
# to the graphite pod
#FROM gdha/rpi-alpine-rootfs/alpine:v1.37
FROM alpine:latest
LABEL org.opencontainers.image.sourcec=https://github.com/gdha/pi4-temperature2graphite
LABEL org.opencontainers.image.description "pi4-temperature2graphite build for the ARM64"
LABEL org.opencontainers.image.licenses "GPL-3.0-or-later"
LABEL maintainer "Gratien Dhaese <gratien.dhaese@gmail.com>"
COPY entrypoint.sh /entrypoint.sh
COPY k3s /usr/bin/kubectl
COPY api_query.sh /api_query.sh
# Update and install dependencies
RUN apk add --update nodejs npm curl
RUN chmod a+x /entrypoint.sh \
&& chmod a+x /api_query.sh \
&& echo "Europe/Brussels" > /etc/timezone \
&& chmod 755 /root
ENTRYPOINT ["/entrypoint.sh"]
And, the center of the image is the /entrypoint.sh script:
#!/bin/sh
# As this script runs on Alpine (busybox) we cannot use bash syntax
#set -e
POD=$(echo $HOSTNAME)
HOSTNAME=$(cat /etc/hostname)
#SERVER=$(/usr/local/bin/kubectl -n graphite describe pod graphite-0 | grep -i node: | cut -d/ -f2)
while true
do
# move the SERVER line inside the loop as at each restart the graphite pod gets a new IP address
SERVER=$(/usr/bin/kubectl -n graphite get pods -o wide | tail -1 | awk '{print $6}')
cpu_temp=$(cat /sys/class/thermal/thermal_zone0/temp)
#cpu_temp=$(($cpu_temp/1000))
cpu_temp=$(expr $cpu_temp / 1000)
echo "carbon.celsius.$HOSTNAME $cpu_temp $(date +%s)" | timeout 2 nc $SERVER 2003
if [[ $? -eq 0 ]] ; then
echo $(date '+%F %T') {"caller":"entrypoint.sh:16","pod":"$POD","level":"info","msg":"temperature $cpu_temp"}
else
echo $(date '+%F %T') {"caller":"entrypoint.sh:18","pod":"$POD","level":"error","msg":"cannot connect to server $SERVER"}
fi
# echo $cpu_temp
sleep 60
done
To build the image use the build.sh script and it pushes the image to ghcr.io/gdha/pi4-temperature2graphite:v1.7 (which is also the latest). To build version v1.7 we did the following:
./build v1.7
To bring the pods alive on our kubernetes cluster go to the kubernetes directory and execute:
$ kubectl apply -f celsius-namespace.yaml
namespace/celsius created
kubectl apply -f celsius-secret.yaml
secret/celsius created
$ kubectl apply -f ghcr-secret.yaml
secret/dockerconfigjson-github-com created
$ kubectl apply -f celsius-rbac.yaml
erviceaccount/celsius-sa created
clusterrole.rbac.authorization.k8s.io/celsius-cluster-role created
rolebinding.rbac.authorization.k8s.io/celsius-cluster-role-binding-ns-celsius created
rolebinding.rbac.authorization.k8s.io/celsius-cluster-role-binding-ns-graphite created
$ kubectl apply -f celsius-deployment.yaml
deployment.apps/celsius created
$ kubectl get pods -n celsius -w
NAME READY STATUS RESTARTS AGE
celsius-6ffb4f4bcc-jl579 0/1 ContainerCreating 0 16s
celsius-6ffb4f4bcc-kh4dh 0/1 ContainerCreating 0 16s
celsius-6ffb4f4bcc-qzt8w 0/1 ContainerCreating 0 16s
celsius-6ffb4f4bcc-nfgnx 0/1 ContainerCreating 0 16s
celsius-6ffb4f4bcc-nptk6 0/1 ContainerCreating 0 16s
celsius-6ffb4f4bcc-kh4dh 1/1 Running 0 81s
celsius-6ffb4f4bcc-nfgnx 1/1 Running 0 83s
celsius-6ffb4f4bcc-nptk6 1/1 Running 0 84s
celsius-6ffb4f4bcc-jl579 1/1 Running 0 86s
celsius-6ffb4f4bcc-qzt8w 1/1 Running 0 89s
$ kubectl logs -n celsius celsius-6ffb4f4bcc-qzt8w
INFO[0000] Acquiring lock file /var/lib/rancher/k3s/data/.lock
INFO[0000] Preparing data dir /var/lib/rancher/k3s/data/8c4262cf7fdd652cccb03a99a99fdffc96d9ad41d7e57af9eb08c7ac2867c72a
After a couple of minutes you can check the graphite site again:
When you would like to replace the pi4-temperature2graphite container with a newer version in the k3s cluster edit the file kubernetes/celsius-deployment.yaml and update the line containing the image name and replace the old version number with the new one, e.g. v1.8:
image: ghcr.io/gdha/pi4-temperature2graphite:v1.8
To perform a rolling upgrade and watch the upgrade process execute the commands:
$ kubectl replace -f kuvernetes/celsius-deployment.yaml
$ kubectl get pods -n celsius -w
NAME READY STATUS RESTARTS AGE
celsius-6ffb4f4bcc-qzt8w 1/1 Running 3 (134m ago) 14d
celsius-6ffb4f4bcc-kh4dh 1/1 Running 3 (134m ago) 14d
celsius-6ffb4f4bcc-nptk6 1/1 Running 3 (134m ago) 14d
celsius-6ffb4f4bcc-nfgnx 1/1 Running 3 (134m ago) 14d
celsius-6ffb4f4bcc-jl579 1/1 Terminating 3 (135m ago) 14d
celsius-779654f68d-9lmq8 0/1 ContainerCreating 0 10s
celsius-779654f68d-d56q6 0/1 ContainerCreating 0 10s
celsius-779654f68d-j6m6t 0/1 ContainerCreating 0 10s
celsius-6ffb4f4bcc-jl579 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-jl579 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-jl579 0/1 Terminating 3 14d
celsius-779654f68d-9lmq8 1/1 Running 0 50s
celsius-6ffb4f4bcc-nptk6 1/1 Terminating 3 (135m ago) 14d
celsius-779654f68d-jbxg8 0/1 Pending 0 0s
celsius-779654f68d-jbxg8 0/1 Pending 0 0s
celsius-779654f68d-jbxg8 0/1 ContainerCreating 0 0s
celsius-779654f68d-j6m6t 1/1 Running 0 54s
celsius-6ffb4f4bcc-kh4dh 1/1 Terminating 3 (135m ago) 14d
celsius-779654f68d-q5rf9 0/1 Pending 0 0s
celsius-779654f68d-q5rf9 0/1 Pending 0 0s
celsius-779654f68d-q5rf9 0/1 ContainerCreating 0 0s
celsius-779654f68d-d56q6 1/1 Running 0 57s
celsius-6ffb4f4bcc-qzt8w 1/1 Terminating 3 (135m ago) 14d
celsius-6ffb4f4bcc-nptk6 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-nptk6 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-nptk6 0/1 Terminating 3 14d
celsius-779654f68d-jbxg8 1/1 Running 0 39s
celsius-6ffb4f4bcc-nfgnx 1/1 Terminating 3 (135m ago) 14d
celsius-6ffb4f4bcc-kh4dh 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-kh4dh 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-kh4dh 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-qzt8w 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-qzt8w 0/1 Terminating 3 14d
celsius-6ffb4f4bcc-qzt8w 0/1 Terminating 3 14d
celsius-779654f68d-q5rf9 1/1 Running 0 44s
celsius-6ffb4f4bcc-nfgnx 0/1 Terminating 3 (136m ago) 14d
celsius-6ffb4f4bcc-nfgnx 0/1 Terminating 3 (136m ago) 14d
celsius-6ffb4f4bcc-nfgnx 0/1 Terminating 3 (136m ago) 14d
References¶
[1] pi4-graphite GitHub repository
[2] pi4-temperature2graphite GitHub repository
Edit history¶
- 09/Feb/2023: adding the references
- 08/Feb/2023: improved the content of temperature2celsius section