AWS integrator charm
This charm acts as a proxy to AWS and provides an interface to apply a certain set of changes via IAM roles, profiles, and tags to the instances of the applications that are related to this charm.
When on AWS, this charm can be deployed, granted trust via Juju to access AWS, and then related to an application that supports the interface. The set of permissions that the related application could request is documented in the interface's Requires API documentation.
For example, Charmed Kubernetes has support for this, and can be deployed with the following bundle overlay:
applications: aws-integrator: charm: cs:~containers/aws-integrator num_units: 1 trust: true relations: - ["aws-integrator", "kubernetes-master"] - ["aws-integrator", "kubernetes-worker"]
Then deploy Charmed Kubernetes using this overlay:
juju deploy cs:charmed-kubernetes --overlay ./k8s-aws-overlay.yaml --trust
In addition to the integrator relation, this charm also provides a proxy to the
AWS Relational Database Service (RDS) for charms using the
Charms attached to the
rds-mysql relation endpoint will have an RDS MySQL
database instance created for them and access information provided via the relation.
For example, if this was deployed alongside the Mediawiki charm, it could provide the database for backing the wiki:
applications: aws-integrator: charm: cs:~containers/aws-integrator num_units: 1 trust: true mediawiki: charm: cs:mediawiki num_units; 1 relations: - ['aws-integrator:rds-mysql', 'mediawiki:db']
The credentials given to the charm must include the following access rights:
Note that these may be different from the permissions that Juju requires to operate.
Resource Usage Note
By relating to this charm, other charms can directly allocate resources, such as EBS volumes and ELBs, which could lead to cloud charges and count against quotas. Because these resources are not managed by Juju, they will not be automatically deleted when the models or applications are destroyed, nor will they show up in Juju's status or GUI. It is therefore up to the operator to manually delete these resources when they are no longer needed, using the AWS console or API.
Following are some examples using AWS integration with Charmed Kubernetes.
Creating a pod with an EBS-backed volume
This script creates a busybox pod with a persistent volume claim backed by AWS's Elastic Block Storage.
#!/bin/bash # create a storage class using the `kubernetes.io/aws-ebs` provisioner kubectl create -f - <<EOY apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: ebs-1 provisioner: kubernetes.io/aws-ebs parameters: type: gp2 EOY # create a persistent volume claim using that storage class kubectl create -f - <<EOY kind: PersistentVolumeClaim apiVersion: v1 metadata: name: testclaim spec: accessModes: - ReadWriteOnce resources: requests: storage: 100Mi storageClassName: ebs-1 EOY # create the busybox pod with a volume using that PVC: kubectl create -f - <<EOY apiVersion: v1 kind: Pod metadata: name: busybox namespace: default spec: containers: - image: busybox command: - sleep - "3600" imagePullPolicy: IfNotPresent name: busybox volumeMounts: - mountPath: "/pv" name: testvolume restartPolicy: Always volumes: - name: testvolume persistentVolumeClaim: claimName: testclaim EOY
Creating a service with an AWS load-balancer
The following script starts the hello-world pod behind an AWS Elastic Load Balancer.
kubectl create deployment hello-world --image=gcr.io/google-samples/node-hello:1.0 kubectl scale deployment hello-world --replicas=5 kubectl expose deployment hello-world --type=LoadBalancer --name=hello --port=8080 watch kubectl get svc hello -o wide
|access-key||string||An IAM access key. It is strongly recommended that you use 'juju trust' instead, if available.|
|secret-key||string||An IAM secret key. It is strongly recommended that you use 'juju trust' instead, if available.|
|snap_proxy||string||DEPRECATED. Use snap-http-proxy and snap-https-proxy model configuration settings. HTTP/HTTPS web proxy for Snappy to use when accessing the snap store.|
|snap_proxy_url||string||DEPRECATED. Use snap-store-proxy model configuration setting. The address of a Snap Store Proxy to use for snaps e.g. http://snap-proxy.example.com|
The base64-encoded contents of an AWS credentials file, which must include both 'aws_access_key_id' and 'aws_secret_access_key' fields.
This can be used from bundles with 'include-base64://' (see https://discourse.charmhub.io/t/bundle-reference/1158), or from the command-line with 'juju config aws credentials="$(base64 /path/to/file)"'.
It is strongly recommended that you use 'juju trust' instead, if available. This will take precedence over the 'access-key' / 'secret-key' config options.
How often snapd handles updates for installed snaps. The default (an empty string) is 4x per day. Set to "max" to check once per month based on the charm deployment date. You may also set a custom string as described in the 'refresh.timer' section here: https://forum.snapcraft.io/t/system-options/87