data "openstack_images_image_v2" "os" {
  name        = var.image_name
  most_recent = true
}

data "openstack_networking_network_v2" "external" {
  name = var.external_network
}

resource "openstack_networking_network_v2" "private" {
  name           = "${var.app_name}-private"
  admin_state_up = true
}

resource "openstack_networking_subnet_v2" "private" {
  name            = "${var.app_name}-private-sn"
  network_id      = openstack_networking_network_v2.private.id
  cidr            = var.private_cidr
  ip_version      = 4
  enable_dhcp     = true
  dns_nameservers = ["8.8.8.8", "8.8.4.4"]
}

resource "openstack_networking_router_v2" "router" {
  name                = "${var.app_name}-router"
  external_network_id = data.openstack_networking_network_v2.external.id
  admin_state_up      = true
}

resource "openstack_networking_router_interface_v2" "private" {
  router_id = openstack_networking_router_v2.router.id
  subnet_id = openstack_networking_subnet_v2.private.id
}

resource "openstack_networking_secgroup_v2" "cache" {
  name        = "${var.app_name}-sg"
  description = "SSH from any IPv4; cache port from the private CIDR only"
}

resource "openstack_networking_secgroup_rule_v2" "cache" {
  direction         = "ingress"
  ethertype         = "IPv4"
  protocol          = "tcp"
  port_range_min    = var.redis_port
  port_range_max    = var.redis_port
  remote_ip_prefix  = var.private_cidr
  security_group_id = openstack_networking_secgroup_v2.cache.id
}

resource "openstack_networking_secgroup_rule_v2" "ssh" {
  direction         = "ingress"
  ethertype         = "IPv4"
  protocol          = "tcp"
  port_range_min    = 22
  port_range_max    = 22
  remote_ip_prefix  = "0.0.0.0/0"
  security_group_id = openstack_networking_secgroup_v2.cache.id
}

resource "openstack_blockstorage_volume_v3" "cache_data" {
  count = var.persistence_enabled ? 1 : 0
  name  = "${var.app_name}-data"
  size  = var.volume_size
}

resource "openstack_networking_port_v2" "cache" {
  name               = "${var.app_name}-port"
  network_id         = openstack_networking_network_v2.private.id
  security_group_ids = [openstack_networking_secgroup_v2.cache.id]

  fixed_ip {
    subnet_id = openstack_networking_subnet_v2.private.id
  }

  depends_on = [openstack_networking_router_interface_v2.private]
}

resource "openstack_compute_instance_v2" "cache" {
  name        = var.app_name
  flavor_name = var.flavor_name
  key_pair    = var.key_name

  user_data = templatefile("${path.module}/cloud-init/redis.yaml", {
    redis_image         = var.redis_image
    server_command      = var.server_command
    redis_port          = var.redis_port
    redis_password      = var.redis_password
    app_name            = var.app_name
    persistence_enabled = var.persistence_enabled
    appendonly          = var.persistence_enabled ? "yes" : "no"
  })

  block_device {
    uuid                  = data.openstack_images_image_v2.os.id
    source_type           = "image"
    destination_type      = "volume"
    volume_size           = 20
    boot_index            = 0
    delete_on_termination = true
  }

  network {
    port = openstack_networking_port_v2.cache.id
  }
}

resource "openstack_compute_volume_attach_v2" "cache_data" {
  count       = var.persistence_enabled ? 1 : 0
  instance_id = openstack_compute_instance_v2.cache.id
  volume_id   = openstack_blockstorage_volume_v3.cache_data[0].id
}

variable "key_name" {
  description = "SSH keypair name (must already exist in your project)"
  type        = string
}

variable "redis_password" {
  description = "Password for the cache (requirepass). Required, no default, so no credential ships with the template."
  type        = string
  sensitive   = true
}

variable "redis_image" {
  description = "Container image for the cache engine. Defaults to Valkey, the BSD-licensed Redis fork. For Redis OSS, set this to redis:7-alpine and set server_command to redis-server."
  type        = string
  default     = "valkey/valkey:8-alpine"
}

variable "server_command" {
  description = "Server binary the image runs. valkey-server for Valkey, redis-server for Redis OSS."
  type        = string
  default     = "valkey-server"
}

variable "flavor_name" {
  description = "Instance size"
  type        = string
  default     = "s1a.small"
}

variable "image_name" {
  description = "Operating system image"
  type        = string
  default     = "Ubuntu-24.04"
}

variable "app_name" {
  description = "Display name prefix for compute and network resources, and the container name"
  type        = string
  default     = "redis-cache"
}

variable "redis_port" {
  description = "Port the cache listens on, bound to the private interface only"
  type        = number
  default     = 6379
}

variable "persistence_enabled" {
  description = "When true, attach a block volume and enable append-only persistence. When false, the cache is in-memory only and data is lost on restart."
  type        = bool
  default     = true
}

variable "volume_size" {
  description = "Block volume size in GiB for persistence (used only when persistence_enabled is true)"
  type        = number
  default     = 10
}

variable "external_network" {
  description = "Shared external network for router gateway and floating IPs; defaults to PublicStatic (persisted FIP / production pattern). Override with PublicEphemeral for ephemeral demos."
  type        = string
  default     = "PublicStatic"
}

variable "private_cidr" {
  description = "CIDR for the private tenant network. The cache port is reachable only from this range."
  type        = string
  default     = "10.20.0.0/24"
}

# Required: SSH keypair must already exist in your project
key_name = "YOUR_KEY_NAME"

# Required: the cache password (requirepass). No default ships with the template.
redis_password = "YOUR_STRONG_PASSWORD"

# Optional: engine and sizing
# redis_image = "valkey/valkey:8-alpine"   # for Redis OSS: "redis:7-alpine"
# server_command = "valkey-server"          # for Redis OSS: "redis-server"
# flavor_name = "s1a.small"
# image_name = "Ubuntu-24.04"
# app_name = "redis-cache"
# redis_port = 6379

# Optional: persistence (append-only on a block volume). Set false for in-memory only.
# persistence_enabled = true
# volume_size = 10

# Optional: networking
# external_network = "PublicStatic"
# private_cidr = "10.20.0.0/24"

#cloud-config
package_update: true
packages:
  - ca-certificates
  - curl
write_files:
  - path: /etc/valkey/valkey.conf
    owner: root:root
    permissions: "0644"
    content: |
      port ${redis_port}
      requirepass ${redis_password}
      appendonly ${appendonly}
      dir /data
runcmd:
  - |
    set -e
    %{ if persistence_enabled ~}
    # The data volume attaches as /dev/sdb on this platform (not /dev/vdb).
    DEV=/dev/sdb
    for i in $(seq 1 30); do [ -b "$DEV" ] && break; sleep 5; done
    if ! blkid "$DEV" >/dev/null 2>&1; then mkfs.ext4 -F -L redisdata "$DEV"; fi
    mkdir -p /data
    mount "$DEV" /data
    grep -q "$DEV" /etc/fstab || echo "$DEV /data ext4 defaults,nofail 0 2" >> /etc/fstab
    %{ else ~}
    mkdir -p /data
    %{ endif ~}
    PRIVATE_IP=$(hostname -I | awk '{print $1}')
    curl -fsSL https://get.docker.com | sh
    systemctl enable --now docker
    docker pull ${redis_image}
    docker run -d --name ${app_name} --restart unless-stopped \
      -p $PRIVATE_IP:${redis_port}:${redis_port} \
      -v /data:/data \
      -v /etc/valkey/valkey.conf:/etc/valkey/valkey.conf:ro \
      ${redis_image} ${server_command} /etc/valkey/valkey.conf

# Redis / Valkey cache

Single compute instance running Valkey (or Redis OSS) in Docker on a private network, for use as a cache, session store, or queue backend. The cache port is reachable only from the private CIDR; the instance has no floating IP. This is the self-hosted equivalent of a hosted Redis service.


**Network class:** production — `external_network` defaults to `PublicStatic` for persisted floating IPs and multi-tier stacks; override with `PublicEphemeral` for ephemeral demos.

Valkey is the default engine. Valkey is the BSD-3-Clause licensed fork of Redis created after Redis OSS moved to the RSALv2 / SSPLv1 source-available license in 2024. To run Redis OSS instead, set `redis_image = "redis:7-alpine"` and `server_command = "redis-server"`.

## quake.yaml mapping

A `redis` service in a launch manifest resolves to this template. The launch handoff applies it before the runtime and passes the resolved connection details to the app as a named environment variable.

| `quake.yaml` field | Maps to |
| --- | --- |
| `services: [{ type: redis }]` | This template |
| resolved `private_ip` and `redis_port` | A `REDIS_URL` injected into the runtime's `container_env` (you supply the password) |

## Prerequisites

- OpenTofu >= 1.6.0 or Terraform >= 1.6.0
- Quake AI account with OpenStack credentials
- An existing SSH keypair in your project (the value of `key_name` must match that keypair)
- A peer on the same private network to reach the cache (an app instance, or a bastion). The cache is not exposed on a floating IP.

## Usage

1. Clone or copy this template directory
2. Copy `terraform.tfvars.example` to `terraform.tfvars` and set `key_name` and `redis_password`
3. Source your OpenStack credentials: `source openrc.sh`
4. Initialize: `tofu init`
5. Preview: `tofu plan`
6. Apply: `tofu apply`

Read `private_ip` and `connection_string_shape` from the outputs. Substitute your password for `REDIS_PASSWORD` in the shape to build the client URL.

## How the instance runs the cache

cloud-init installs Docker, optionally formats and mounts a block volume at `/data`, then runs the engine container:

- The cache binds to the instance's private IP only (`-p PRIVATE_IP:6379:6379`), not `0.0.0.0`.
- `requirepass` is set from `redis_password`, read from a config file mounted read-only.
- With `persistence_enabled = true`, append-only persistence writes to `/data` on the attached volume. With it false, the cache is in-memory only and data is lost on restart.

## Security

- The security group allows the cache port only from `private_cidr`. SSH (22) is the only rule open to `0.0.0.0/0`, and the instance has no floating IP, so the cache is not reachable from the public internet.
- `redis_password` is required with no default, so no credential ships with the template. The password is rendered into the instance's cloud-init data (as with any self-provisioning template); it is not committed to the repository.

## Variables

| Name | Type | Required | Default | Description |
| --- | --- | --- | --- | --- |
| `key_name` | string | yes | n/a | SSH keypair name (must already exist in your project) |
| `redis_password` | string | yes | n/a | Cache password (`requirepass`) |
| `redis_image` | string | no | `valkey/valkey:8-alpine` | Engine image (Redis OSS: `redis:7-alpine`) |
| `server_command` | string | no | `valkey-server` | Server binary (Redis OSS: `redis-server`) |
| `flavor_name` | string | no | `s1a.small` | Instance size |
| `image_name` | string | no | `Ubuntu-24.04` | Operating system image |
| `app_name` | string | no | `redis-cache` | Display name prefix and container name |
| `redis_port` | number | no | `6379` | Port the cache listens on |
| `persistence_enabled` | bool | no | `true` | Attach a volume and enable append-only persistence |
| `volume_size` | number | no | `10` | Persistence volume size in GiB |
| `external_network` | string | no | `PublicStatic` | Persisted FIP / production default; override with `PublicEphemeral` for demos |
| `private_cidr` | string | no | `10.20.0.0/24` | Private subnet CIDR; the only range allowed to reach the cache port |

## Outputs

| Name | Description |
| --- | --- |
| `private_ip` | Private IP of the cache instance |
| `connection_string_shape` | Client URL shape with a `REDIS_PASSWORD` placeholder (no secret emitted) |
| `instance_id` | Compute instance ID |

## Scope

Single-instance cache, not a replicated or highly available cluster. For high availability, run Sentinel or a clustered topology across multiple instances; this template provisions one node.

## Documentation

See also: [self-managed Postgres template](/resources/iac-templates/self-managed-postgres)