[storage] Add an SQL storage driver

This commits adds the possibility to back Tiller (or the future Tiller-less Helm CLI) with any SQL database (only postgres has been tested so far) to store release information. The main motivation for this commit was to use a storage backend that would allow releases larger that 1MB in size (ConfigMap or Secret drivers don't, because of limits on value size in the underlying etcd key-value store). Signed-off-by: Étienne Lafarge <etienne.lafarge@gmail.com> Co-authored-by: Elliot Maincourt <e.maincourt@gmail.com> (@emaincourt) Co-authored-by: Paul Borensztein <hi@0x01.fr> (@commit-master)
helm · Feb 27, 2019 · 33a8fbc · 33a8fbc
1 parent 42e424b
commit 33a8fbc
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diff --git a/cmd/tiller/tiller.go b/cmd/tiller/tiller.go
@@ -65,6 +65,7 @@ const (
 	storageMemory    = "memory"
 	storageConfigMap = "configmap"
 	storageSecret    = "secret"
+	storageSQL       = "sql"
 
 	probeAddr = ":44135"
 	traceAddr = ":44136"
@@ -74,17 +75,22 @@ const (
 )
 
 var (
-	grpcAddr             = flag.String("listen", ":44134", "address:port to listen on")
-	enableTracing        = flag.Bool("trace", false, "enable rpc tracing")
-	store                = flag.String("storage", storageConfigMap, "storage driver to use. One of 'configmap', 'memory', or 'secret'")
+	grpcAddr      = flag.String("listen", ":44134", "address:port to listen on")
+	enableTracing = flag.Bool("trace", false, "enable rpc tracing")
+
+	store               = flag.String("storage", storageConfigMap, "storage driver to use. One of 'configmap', 'memory', 'sql' or 'secret'")
+	sqlDialect          = flag.String("sql-dialect", "postgres", "SQL dialect to use (only postgres is supported for now")
+	sqlConnectionString = flag.String("sql-connection-string", "", "SQL connection string to use")
+
 	remoteReleaseModules = flag.Bool("experimental-release", false, "enable experimental release modules")
-	tlsEnable            = flag.Bool("tls", tlsEnableEnvVarDefault(), "enable TLS")
-	tlsVerify            = flag.Bool("tls-verify", tlsVerifyEnvVarDefault(), "enable TLS and verify remote certificate")
-	keyFile              = flag.String("tls-key", tlsDefaultsFromEnv("tls-key"), "path to TLS private key file")
-	certFile             = flag.String("tls-cert", tlsDefaultsFromEnv("tls-cert"), "path to TLS certificate file")
-	caCertFile           = flag.String("tls-ca-cert", tlsDefaultsFromEnv("tls-ca-cert"), "trust certificates signed by this CA")
-	maxHistory           = flag.Int("history-max", historyMaxFromEnv(), "maximum number of releases kept in release history, with 0 meaning no limit")
-	printVersion         = flag.Bool("version", false, "print the version number")
+
+	tlsEnable    = flag.Bool("tls", tlsEnableEnvVarDefault(), "enable TLS")
+	tlsVerify    = flag.Bool("tls-verify", tlsVerifyEnvVarDefault(), "enable TLS and verify remote certificate")
+	keyFile      = flag.String("tls-key", tlsDefaultsFromEnv("tls-key"), "path to TLS private key file")
+	certFile     = flag.String("tls-cert", tlsDefaultsFromEnv("tls-cert"), "path to TLS certificate file")
+	caCertFile   = flag.String("tls-ca-cert", tlsDefaultsFromEnv("tls-ca-cert"), "trust certificates signed by this CA")
+	maxHistory   = flag.Int("history-max", historyMaxFromEnv(), "maximum number of releases kept in release history, with 0 meaning no limit")
+	printVersion = flag.Bool("version", false, "print the version number")
 
 	// rootServer is the root gRPC server.
 	//
@@ -141,6 +147,18 @@ func start() {
 
 		env.Releases = storage.Init(secrets)
 		env.Releases.Log = newLogger("storage").Printf
+	case storageSQL:
+		sqlDriver, err := driver.NewSQL(
+			*sqlDialect,
+			*sqlConnectionString,
+			newLogger("storage/driver").Printf,
+		)
+		if err != nil {
+			logger.Fatalf("Cannot initialize SQL storage driver: %v", err)
+		}
+
+		env.Releases = storage.Init(sqlDriver)
+		env.Releases.Log = newLogger("storage").Printf
 	}
 
 	if *maxHistory > 0 {

diff --git a/docs/install.md b/docs/install.md
@@ -353,10 +353,13 @@ in JSON format.
 
 ### Storage backends
 By default, `tiller` stores release information in `ConfigMaps` in the namespace
-where it is running. As of Helm 2.7.0, there is now a beta storage backend that
+where it is running.
+
+#### Secret storage backend
+As of Helm 2.7.0, there is now a beta storage backend that
 uses `Secrets` for storing release information. This was added for additional
-security in protecting charts in conjunction with the release of `Secret` 
-encryption in Kubernetes. 
+security in protecting charts in conjunction with the release of `Secret`
+encryption in Kubernetes.
 
 To enable the secrets backend, you'll need to init Tiller with the following
 options:
@@ -369,6 +372,31 @@ Currently, if you want to switch from the default backend to the secrets
 backend, you'll have to do the migration for this on your own. When this backend
 graduates from beta, there will be a more official path of migration
 
+#### SQL storage backend
+As of Helm 2.14.0 there is now a beta SQL storage backend that stores release
+information in an SQL database (only postgres has been tested so far).
+
+Using such a storage backend is particularly useful if your release information
+weighs more than 1MB (in which case, it can't be stored in ConfigMaps/Secrets
+because of internal limits in Kubernetes' underlying etcd key-value store).
+
+To enable the SQL backend, you'll need to [deploy an SQL
+database](./sql-storage.md) and init Tiller with the following options:
+
+```shell
+helm init \
+  --override \
+    'spec.template.spec.containers[0].args'='{--storage=sql,--sql-dialect=postgres,--sql-connection-string=postgresql://tiller-postgres:5432/helm?user=helm&password=changemeforgodssake&sslmode=disable}'
+```
+
+**PRODUCTION NOTES**: it's recommended to change the username and password of
+the SQL database in production deployments. Enabling SSL is also a good idea.
+Last, but not least, perform regular backups/snapshots of your SQL database.
+
+Currently, if you want to switch from the default backend to the SQL backend,
+you'll have to do the migration for this on your own. When this backend
+graduates from beta, there will be a more official migration path.
+
 ## Conclusion
 
 In most cases, installation is as simple as getting a pre-built `helm` binary

diff --git a/docs/sql-storage.md b/docs/sql-storage.md
@@ -0,0 +1,89 @@
+# Store release information in an SQL database
+
+You may be willing to store release information in an SQL database - in
+particular, if your releases weigh more than 1MB and therefore [can't be stored in ConfigMaps or Secrets](https://github.com/helm/helm/issues/1413).
+
+We recommend using [PostgreSQL](https://www.postgresql.org/).
+
+This document describes how to deploy `postgres` atop Kubernetes. This being
+said, using an out-of-cluster (managed or not) PostreSQL instance is totally
+possible as well.
+
+Here's a Kubernetes manifest you can apply to get a minimal PostreSQL pod
+running on your Kubernetes cluster. **Don't forget to change the credentials
+and, optionally, enable TLS in production deployments**.
+
+```yaml
+apiVersion: v1
+kind: Service
+metadata:
+  name: tiller-postgres
+  namespace: kube-system
+spec:
+  ports:
+    - port: 5432
+  selector:
+    app: helm
+    name: postgres
+---
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: tiller-postgres
+  namespace: kube-system
+spec:
+  serviceName: tiller-postgres
+  selector:
+    matchLabels:
+      app: helm
+      name: postgres
+  replicas: 1
+  template:
+    metadata:
+      labels:
+        app: helm
+        name: postgres
+    spec:
+      containers:
+        - name: postgres
+          image: postgres:11-alpine
+          imagePullPolicy: Always
+          ports:
+            - containerPort: 5432
+          env:
+          - name: POSTGRES_DB
+            value: helm
+          - name: POSTGRES_USER
+            value: helm
+          - name: POSTGRES_PASSWORD
+            value: changemeforgodssake
+          - name: PGDATA
+            value: /var/lib/postgresql/data/pgdata
+          resources:
+            limits:
+              memory: 128Mi
+            requests:
+              cpu: 50m
+              memory: 128Mi
+          volumeMounts:
+            - mountPath: /var/lib/postgresql/data
+              name: tiller-postgres-data
+  volumeClaimTemplates:
+  - metadata:
+      name: tiller-postgres-data
+    spec:
+      accessModes: ["ReadWriteOnce"]
+      storageClassName: default
+      resources:
+        requests:
+          storage: 5Gi
+```
+
+Once postgres is deployed, you'll need to install Tiller using `helm init`, with
+a few custom CLI flags:
+
+```shell
+helm init \
+  --override \
+    'spec.template.spec.containers[0].args'='{--storage=sql,--sql-dialect=postgres,--sql-connection-string=postgresql://tiller-postgres:5432/helm?user=helm&password=changemeforgodssake&sslmode=disable}'
+```
diff --git a/glide.lock b/glide.lock