Vault Bootstrap

Alternative: kubevault/unsealer

About

This tool can be used to initialize Hashicorp Vault on Kubernetes. It can perform the following steps:

• Vault initilazation
• Save Root Token and Unseal Keys to K8s Secret
• Vault unseal
• Enable Kubernetes authentication

Disclaimer

In this version, the Vault token and unseal Keys can only be saved to a Kubernetes secret. This is insecure and this deployment is ONLY SUITED FOR DEVELOPMENT ENVIRONMENTS. However, this tool can be extended to save Vault token and unseal Keys to a different secret engine (Azure Key Vault, AWS KMS, another Vault instance).

Usage

Docker Image: ghcr.io/spirkaa/vault-bootstrap*

Scenario 1 - Job

To install Vault Bootstrap to OpenShift or Kubernetes, deploy the following Job:

cat <<EOF | oc apply -f
apiVersion: batch/v1
kind: Job
metadata:
  name: vault
  namespace: vault
spec:
  backoffLimit: 3
  template:
    spec:
      serviceAccount: vault
      restartPolicy: Never
      containers:
      - name: vault-init
        image: ghcr.io/spirkaa/vault-bootstrap:latest
        env:
        - name: VAULT_ADDR
          value: "https://vault.vault:8200"
        - name: VAULT_CLUSTER_MEMBERS
          value: >-
            https://vault-0.vault-internal:8200,https://vault-1.vault-internal:8200,https://vault-2.vault-internal:8200
        - name: VAULT_KEY_SHARES
          value: "5"
        - name: VAULT_KEY_THRESHOLD
          value: "3"
        - name: VAULT_ENABLE_INIT
          value: "true"
        - name: VAULT_ENABLE_K8SSECRET
          value: "true"
        - name: VAULT_ENABLE_UNSEAL
          value: "true"
        - name: VAULT_ENABLE_K8SAUTH
          value: "true"
        - name: VAULT_K8SAUTH_SERVICE_ACCOUNT
          value: vault-external-secrets
        - name: NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        imagePullPolicy: Always
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: vault
  name: vault
rules:
- apiGroups:
  - ""
  resources:
  - "pods"
  verbs:
  - "get"
  - "list"
  - "watch"
- apiGroups:
  - ""
  resources:
  - "secrets"
  verbs:
  - "get"
  - "list"
  - "watch"
  - "create"
- apiGroups:
  - ""
  resources:
  - "serviceaccounts"
  verbs:
  - "get"
  - "list"
  - "watch"
- apiGroups:
  - "batch"
  resources:
  - "jobs"
  verbs:
  - "get"
  - "list"
  - "watch"
  - "create"
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: vault
  namespace: vault
subjects:
- kind: ServiceAccount
  name: vault
  namespace: vault
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: vault
EOF

If you are choosing to save the root token and unseal keys into a Kubernetes secret, you can re-run the init job for unsealing any of the pods (in case in gets rescheduled). To do this, run the following command

oc get job vault-init -o json | jq 'del(.spec.selector)' | jq 'del(.spec.template.metadata.labels)' | oc replace --force -f -

Scenario 2 - Init Container

This tool can be run in init-container mode, which can be used if we want to perform auto-unsealing from K8s secret. In this mode, the initContainer will spawn up a vault-bootstrap job configured to perform only unsealing only for the pods attached to. To perform this scenario, add the following definition to the Vault StatefulSet definition

initContainers:
- name: vault-bootstrap
  image: ghcr.io/spirkaa/vault-bootstrap:latest
  command:
    - /vault-bootstrap
  args:
    - --mode
    - init-container
  env:
    - name: VAULT_ADDR
      value: "http://vault.vault:8200"
    - name: VAULT_CLUSTER_MEMBERS
      value: >-
        http://vault-0.vault-internal.vault:8200
    - name: VAULT_KEY_SHARES
      value: "5"
    - name: VAULT_KEY_THRESHOLD
      value: "3"
    - name: VAULT_ENABLE_INIT
      value: "true"
    - name: VAULT_ENABLE_K8SSECRET
      value: "true"
    - name: VAULT_ENABLE_UNSEAL
      value: "true"
    - name: VAULT_ENABLE_K8SAUTH
      value: "true"
    - name: VAULT_K8SAUTH_SERVICE_ACCOUNT
      value: vault-external-secrets
    - name: VAULT_K8S_POD_NAME
          valueFrom:
            fieldRef:
              fieldPath: metadata.name

Configuration

The configurations are specified as Environment variables. Below the supported ones.

Environment Variable	Default value	Info
VAULT_ADDR	https://vault:8200	Vault address
VAULT_CLUSTER_MEMBERS	https://vault:8200	Vault cluster members as URLs specified in a comma separated list
VAULT_KEY_SHARES	1	Key Shares generated by initialization
VAULT_KEY_THRESHOLD	1	Key Threshold generated by initialization
VAULT_ENABLE_INIT	true	Enable Vault initialization
VAULT_ENABLE_K8SSSECRET	true	Enable saving Vault root token and share keys into a K8s secrets
VAULT_ENABLE_UNSEAL	true	Enable Vault unseal
VAULT_ENABLE_K8SAUTH	true	Enable Kubernetes authentication for Vault
VAULT_SERVICE_ACCOUNT	vault	Service account for job pod
VAULT_K8SAUTH_SERVICE_ACCOUNT	vault	Service account for K8s authentication
VAULT_K8S_POD_NAME	N/A	Relevant only for init-container mode.