Refactor db-migration-worker deployment

Instead of creating a deployment with a replica set, we just create the
pod once. Also the pod should have everything in the future to run the
database migration. Ie. have `cypher-shell` to write directly to the
database in the current network. All required configuration is passed
manually to the `db-migration-worker`-pod directly. SSH-keys are copied
through a secrets file. This altogether made many configuration files
obsolete.

.gitignore

@@ -0,0 +1,2 @@
+secrets.yaml
+*/secrets.yaml

README.md

@@ -109,20 +109,38 @@ Wait until all pods turn green and they don't show a warning
 `Waiting: ContainerCreating` anymore.
 
 
-### Provision db-migration-worker
-Copy your private ssh key and the `.known-hosts` file of your remote legacy
-server.
-```shell
-
-# check the corresponding db-migration-worker pod
-$ kubectl --namespace=staging get pods
-# change <POD_ID> below
-$ kubectl cp path/to/your/ssh/keys/.ssh staging/nitro-db-migration-worker-<POD_ID>:/root/
+### Migrate database of Human Connection legacy server
+Create a configmap with the specific connection data of your legacy server:
+```sh
+$ kubectl create configmap db-migration-worker   \
+  --namespace=staging                            \
+  --from-literal=SSH_USERNAME=someuser           \
+  --from-literal=SSH_HOST=yourhost               \
+  --from-literal=MONGODB_USERNAME=hc-api         \
+  --from-literal=MONGODB_PASSWORD=secretpassword \
+  --from-literal=MONGODB_AUTH_DB=hc_api          \
+  --from-literal=MONGODB_DATABASE=hc_api         \
+  --from-literal=UPLOADS_DIRECTORY=/var/www/api/uploads
 ```
+Create a secret with your public and private ssh keys:
+```sh
+$ kubectl create secret generic ssh-keys          \
+  --namespace=staging                             \
+  --from-file=id_rsa=/path/to/.ssh/id_rsa         \
+  --from-file=id_rsa.pub=/path/to/.ssh/id_rsa.pub \
+  --from-file=known_hosts=/path/to/.ssh/known_hosts
+```
+As the [kubernetes documentation](https://kubernetes.io/docs/concepts/configuration/secret/#use-case-pod-with-ssh-keys)
+points out, you should be careful with your ssh keys. Anyone with access to your
+cluster will have access to your ssh keys. Better create a new pair with
+`ssh-keygen` and copy the public key to your legacy server with `ssh-copy-id`.
 
+Create the pod and the required volume:
+```sh
+$ kubectl apply -f db-migration-worker.yaml
+```
 Run the migration:
 ```shell
 # change <POD_IDs> below
-$ kubectl --namespace=staging exec -it nitro-db-migration-worker-<POD_ID> ./import.sh
-$ kubectl --namespace=staging exec -it nitro-neo4j-<POD_ID>               ./import/import.sh
+$ kubectl --namespace=staging exec -it nitro-db-migration-worker ./import.sh
 ```

configmap-db-migration-worker.template.yaml

@@ -1,12 +0,0 @@
-apiVersion: v1
-kind: ConfigMap
-data:
-  SSH_USERNAME: "<REPLACE>"
-  SSH_HOST: "<REPLACE>"
-  MONGODB_USERNAME: "hc-api"
-  MONGODB_AUTH_DB: "hc_api"
-  MONGODB_DATABASE: "hc_api"
-  UPLOADS_DIRECTORY: "/var/www/api/uploads"
-metadata:
-  name: staging-db-migration-worker
-  namespace: staging

db-migration-worker.yaml

@@ -0,0 +1,39 @@
+---
+  kind: Pod
+  apiVersion: v1
+  metadata:
+    name: nitro-db-migration-worker
+    namespace: staging
+  spec:
+    volumes:
+    - name: secret-volume
+      secret:
+        secretName: ssh-keys
+        defaultMode: 0400
+    - name: mongo-export
+      persistentVolumeClaim:
+        claimName: mongo-export-claim
+    containers:
+    - name: nitro-db-migration-worker
+      image: humanconnection/db-migration-worker:latest
+      envFrom:
+      - configMapRef:
+          name: db-migration-worker
+      volumeMounts:
+      - name: secret-volume
+        readOnly: false
+        mountPath: /root/.ssh
+      - name: mongo-export
+        mountPath: /mongo-export/
+---
+  kind: PersistentVolumeClaim
+  apiVersion: v1
+  metadata:
+    name: mongo-export-claim
+    namespace: staging
+  spec:
+    accessModes:
+      - ReadWriteOnce
+    resources:
+      requests:
+        storage: 1Gi

staging/.gitignore

@@ -1,2 +0,0 @@
-configmap-db-migration-worker.yaml
-secrets.yaml

staging/deployment-db-migration-worker.yaml

@@ -1,92 +0,0 @@
----
-  apiVersion: extensions/v1beta1
-  kind: Deployment
-  metadata:
-    name: nitro-db-migration-worker
-    namespace: staging
-  spec:
-    replicas: 1
-    minReadySeconds: 15
-    progressDeadlineSeconds: 60
-    selector:
-      matchLabels:
-        workload.user.cattle.io/workloadselector: deployment-staging-db-migration-worker
-    template:
-      metadata:
-        labels:
-          workload.user.cattle.io/workloadselector: deployment-staging-db-migration-worker
-        name: nitro-db-migration-worker
-      spec:
-        containers:
-        - env:
-          - name: COMMIT
-            value: <BACKEND_COMMIT>
-          - name: SSH_USERNAME
-            valueFrom:
-              configMapKeyRef:
-                name: staging-db-migration-worker
-                key: SSH_USERNAME
-          - name: SSH_HOST
-            valueFrom:
-              configMapKeyRef:
-                name: staging-db-migration-worker
-                key: SSH_HOST
-          - name: MONGODB_USERNAME
-            valueFrom:
-              configMapKeyRef:
-                name: staging-db-migration-worker
-                key: MONGODB_USERNAME
-          - name: MONGODB_AUTH_DB
-            valueFrom:
-              configMapKeyRef:
-                name: staging-db-migration-worker
-                key: MONGODB_AUTH_DB
-          - name: MONGODB_DATABASE
-            valueFrom:
-              configMapKeyRef:
-                name: staging-db-migration-worker
-                key: MONGODB_DATABASE
-          - name: UPLOADS_DIRECTORY
-            valueFrom:
-              configMapKeyRef:
-                name: staging-db-migration-worker
-                key: UPLOADS_DIRECTORY
-          - name: MONGODB_PASSWORD
-            valueFrom:
-              secretKeyRef:
-                name: staging
-                key: MONGODB_PASSWORD
-                optional: false
-          image: humanconnection/db-migration-worker:latest
-          name: nitro-db-migration-worker
-          resources: {}
-          imagePullPolicy: Always
-          volumeMounts:
-            - mountPath: /root/
-              name: ssh-keys-directory
-            - mountPath: /mongo-export/
-              name: mongo-export
-        volumes:
-        - name: ssh-keys-directory
-          persistentVolumeClaim:
-            claimName: ssh-keys-claim
-        - name: mongo-export
-          persistentVolumeClaim:
-            claimName: mongo-export-claim
-        restartPolicy: Always
-        terminationGracePeriodSeconds: 30
-  status: {}
----
-  kind: PersistentVolumeClaim
-  apiVersion: v1
-  metadata:
-    name: ssh-keys-claim
-    namespace: staging
-  spec:
-    accessModes:
-      - ReadWriteOnce
-    resources:
-      requests:
-        # waaay too much
-        # unfortunately Digital Oceans volumes start at 1Gi
-        storage: 1Gi

staging/volume-claim-mongo-exports.yaml

@@ -1,12 +0,0 @@
----
-  kind: PersistentVolumeClaim
-  apiVersion: v1
-  metadata:
-    name: mongo-export-claim
-    namespace: staging
-  spec:
-    accessModes:
-      - ReadWriteOnce
-    resources:
-      requests:
-        storage: 1Gi

staging/volume-claim-uploads.yaml

@@ -1,12 +0,0 @@
----
-  kind: PersistentVolumeClaim
-  apiVersion: v1
-  metadata:
-    name: uploads-claim
-    namespace: staging
-  spec:
-    accessModes:
-      - ReadWriteOnce
-    resources:
-      requests:
-        storage: 8Gi