# 08 - Prod DB Cluster Kurulumu (Swarm)

Bu aşamanın amacı üç DB node'unu Docker Swarm'a worker olarak eklemek, MongoDB replica set ve Patroni + etcd ile yönetilen PostgreSQL yüksek erişilebilirlik konfigürasyonunu yapmaktır.

`07-prod-ansible-bootstrap.md` tüm DB node'larında tamamlanmış olmalıdır.

## Mimari

```
iklim-app-01/02/03  (Swarm manager'lar, 10.20.10.11/12/13)
        |
        |-- iklimco-net (overlay)
        |
iklim-db-01  (Swarm worker, 10.20.20.11)
    mongodb-01   [rs0 member 0 — preferred primary]
    etcd-01      [etcd cluster member]
    patroni-01   [Patroni + PostgreSQL — ilk primary adayı]

iklim-db-02  (Swarm worker, 10.20.20.12)
    mongodb-02   [rs0 member 1]
    etcd-02      [etcd cluster member]
    patroni-02   [Patroni + PostgreSQL — standby]

iklim-db-03  (Swarm worker, 10.20.20.13)
    mongodb-03   [rs0 member 2]
    etcd-03      [etcd cluster member]
    patroni-03   [Patroni + PostgreSQL — standby]
```

DB container'ları birbirlerini overlay DNS adıyla değil, **Hetzner private IP üzerinden** tanıyor. Bu nedenle her servis portunu `host` modda yayımlar; replikasyon ve etcd trafiği doğrudan private network üzerinden gecer. Hetzner Cloud firewall ve prod `db` firewall zaten bu portlara izin vermektedir.

## 1. Firewall Güncellemesi

`terraform/hetzner/prod/firewall.tf` dosyasında aşağıdaki kuralların mevcut olduğunu doğrula; eksik varsa ekle ve `terraform apply` çalıştır.

`hcloud_firewall.swarm` içinde (DB subnet'ten Swarm portlarına):

```hcl
rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "2377"
  source_ips  = [local.db_subnet_cidr]
  description = "Docker Swarm control plane from DB subnet"
}

rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "7946"
  source_ips  = [local.db_subnet_cidr]
  description = "Docker Swarm node discovery (TCP) from DB subnet"
}

rule {
  direction   = "in"
  protocol    = "udp"
  port        = "7946"
  source_ips  = [local.db_subnet_cidr]
  description = "Docker Swarm node discovery (UDP) from DB subnet"
}

rule {
  direction   = "in"
  protocol    = "udp"
  port        = "4789"
  source_ips  = [local.db_subnet_cidr]
  description = "Docker Swarm VXLAN overlay from DB subnet"
}
```

`hcloud_firewall.db` içinde (app subnet'ten Swarm portlarına + overlay; DB subnet içi etcd/Patroni trafiği):

```hcl
rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "2377"
  source_ips  = [local.app_subnet_cidr]
  description = "Docker Swarm control plane from app subnet"
}

rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "7946"
  source_ips  = [local.app_subnet_cidr]
  description = "Docker Swarm node discovery (TCP) from app subnet"
}

rule {
  direction   = "in"
  protocol    = "udp"
  port        = "7946"
  source_ips  = [local.app_subnet_cidr]
  description = "Docker Swarm node discovery (UDP) from app subnet"
}

rule {
  direction   = "in"
  protocol    = "udp"
  port        = "4789"
  source_ips  = [local.app_subnet_cidr]
  description = "Docker Swarm VXLAN overlay from app subnet"
}

rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "2379"
  source_ips  = [local.db_subnet_cidr]
  description = "etcd client port within DB subnet"
}

rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "2380"
  source_ips  = [local.db_subnet_cidr]
  description = "etcd peer port within DB subnet"
}

rule {
  direction   = "in"
  protocol    = "tcp"
  port        = "8008"
  source_ips  = [local.db_subnet_cidr]
  description = "Patroni REST API within DB subnet"
}
```

```bash
cd terraform/hetzner/prod
terraform plan
terraform apply
```

## 2. DB Node'larını Swarm'a Ekleme

**Swarm manager'lardan birinde** (iklim-app-01) join token al:

```bash
docker swarm join-token worker
```

**Her DB node'unda** (iklim-db-01, iklim-db-02, iklim-db-03):

```bash
docker swarm join --token <TOKEN> 10.20.10.11:2377
```

**iklim-app-01 üzerinde** node'ları etiketle:

```bash
docker node update --label-add role=db --label-add db-index=01 iklim-db-01
docker node update --label-add role=db --label-add db-index=02 iklim-db-02
docker node update --label-add role=db --label-add db-index=03 iklim-db-03

docker node ls
```

## 3. StorageBox Dizin Yapısı

Her DB node'unda (`/mnt/storagebox` zaten mount edilmiş olmalı):

```bash
# iklim-db-01 üzerinde:
mkdir -p /mnt/storagebox/prod/db/mongodb-01/{data,log,config}
mkdir -p /mnt/storagebox/prod/db/postgresql-01/{data,config}
mkdir -p /mnt/storagebox/prod/db/etcd-01/data

# iklim-db-02 üzerinde:
mkdir -p /mnt/storagebox/prod/db/mongodb-02/{data,log,config}
mkdir -p /mnt/storagebox/prod/db/postgresql-02/{data,config}
mkdir -p /mnt/storagebox/prod/db/etcd-02/data

# iklim-db-03 üzerinde:
mkdir -p /mnt/storagebox/prod/db/mongodb-03/{data,log,config}
mkdir -p /mnt/storagebox/prod/db/postgresql-03/{data,config}
mkdir -p /mnt/storagebox/prod/db/etcd-03/data
```

## 4. MongoDB Replica Set

### mongod.conf

Her DB node'unda `/mnt/storagebox/prod/db/mongodb-0X/config/mongod.conf`:

```yaml
net:
  port: 27017
storage:
  engine: "wiredTiger"
  dbPath: "/data/db"
  directoryPerDB: true
systemLog:
  verbosity: 0
  timeStampFormat: "iso8601-local"
  destination: file
  path: "/data/log/mongo.log"
  logAppend: true
  logRotate: rename
replication:
  replSetName: "rs0"
security:
  authorization: enabled
  keyFile: "/data/configdb/rs-auth.key"
```

### Replica Set Auth Key

Tüm DB node'larında **aynı** key dosyası olmalıdır:

```bash
# iklim-db-01 üzerinde oluştur:
openssl rand -base64 756 > /mnt/storagebox/prod/db/mongodb-01/config/rs-auth.key
chmod 400 /mnt/storagebox/prod/db/mongodb-01/config/rs-auth.key

# Aynı içeriği diğer node'lara kopyala:
cat /mnt/storagebox/prod/db/mongodb-01/config/rs-auth.key \
  > /mnt/storagebox/prod/db/mongodb-02/config/rs-auth.key
cat /mnt/storagebox/prod/db/mongodb-01/config/rs-auth.key \
  > /mnt/storagebox/prod/db/mongodb-03/config/rs-auth.key

chmod 400 /mnt/storagebox/prod/db/mongodb-0{2,3}/config/rs-auth.key
```

### Stack Dosyası — MongoDB

`/opt/iklimco/stacks/prod-db-mongo.yml`:

```yaml
version: "3.8"

networks:
  iklimco-net:
    external: true

services:
  mongodb-01:
    image: mongo:8
    environment:
      MONGO_INITDB_ROOT_USERNAME: mongo-root
      MONGO_INITDB_ROOT_PASSWORD: "${MONGO_ROOT_PASSWORD}"
    volumes:
      - /mnt/storagebox/prod/db/mongodb-01/data:/data/db
      - /mnt/storagebox/prod/db/mongodb-01/log:/data/log
      - /mnt/storagebox/prod/db/mongodb-01/config:/data/configdb
    networks:
      - iklimco-net
    ports:
      - target: 27017
        published: 27017
        protocol: tcp
        mode: host
    command: ["--config", "/data/configdb/mongod.conf"]
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-01
      restart_policy:
        condition: on-failure

  mongodb-02:
    image: mongo:8
    environment:
      MONGO_INITDB_ROOT_USERNAME: mongo-root
      MONGO_INITDB_ROOT_PASSWORD: "${MONGO_ROOT_PASSWORD}"
    volumes:
      - /mnt/storagebox/prod/db/mongodb-02/data:/data/db
      - /mnt/storagebox/prod/db/mongodb-02/log:/data/log
      - /mnt/storagebox/prod/db/mongodb-02/config:/data/configdb
    networks:
      - iklimco-net
    ports:
      - target: 27017
        published: 27017
        protocol: tcp
        mode: host
    command: ["--config", "/data/configdb/mongod.conf"]
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-02
      restart_policy:
        condition: on-failure

  mongodb-03:
    image: mongo:8
    environment:
      MONGO_INITDB_ROOT_USERNAME: mongo-root
      MONGO_INITDB_ROOT_PASSWORD: "${MONGO_ROOT_PASSWORD}"
    volumes:
      - /mnt/storagebox/prod/db/mongodb-03/data:/data/db
      - /mnt/storagebox/prod/db/mongodb-03/log:/data/log
      - /mnt/storagebox/prod/db/mongodb-03/config:/data/configdb
    networks:
      - iklimco-net
    ports:
      - target: 27017
        published: 27017
        protocol: tcp
        mode: host
    command: ["--config", "/data/configdb/mongod.conf"]
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-03
      restart_policy:
        condition: on-failure
```

### Replica Set Başlangıç

Stack deploy edildikten sonra **bir kez** çalıştırılır:

```bash
# iklim-db-01 üzerinde:
docker exec -it $(docker ps -q -f name=iklim-db_mongodb-01) mongosh \
  -u mongo-root -p "${MONGO_ROOT_PASSWORD}" --authenticationDatabase admin

# mongosh içinde:
rs.initiate({
  _id: "rs0",
  members: [
    { _id: 0, host: "10.20.20.11:27017", priority: 2 },
    { _id: 1, host: "10.20.20.12:27017", priority: 1 },
    { _id: 2, host: "10.20.20.13:27017", priority: 1 }
  ]
})

# Durum kontrol:
rs.status()
```

`"stateStr": "PRIMARY"` ve iki `"SECONDARY"` görülünce replica set hazırdır.

## 5. PostgreSQL — Patroni + etcd

Patroni, PostgreSQL primary/standby rollerini etcd üzerinden koordine eder. Primary düşerse diğer node'lardan biri otomatik olarak seçim kazanır ve primary olur. Swarm servisi container'ı yeniden başlatır; Patroni kaldığı yerden devam eder.

### 5.1 Özel Image (Patroni + PostGIS)

`postgis/postgis:17-3.5` imajı üzerine Patroni kurulur. Bu imaj Harbor'a push edilip stack'te kullanılır.

`Environment_Infrastructure/docker/patroni-postgis/Dockerfile`:

```dockerfile
FROM postgis/postgis:17-3.5

USER root

RUN apt-get update && apt-get install -y --no-install-recommends \
    python3-pip \
    python3-dev \
    gcc \
    libpq-dev \
    && pip3 install --no-cache-dir 'patroni[etcd3]' \
    && apt-get purge -y gcc python3-dev \
    && apt-get autoremove -y \
    && rm -rf /var/lib/apt/lists/*

USER postgres

ENTRYPOINT ["patroni", "/etc/patroni/patroni.yml"]
```

Build ve push:

```bash
cd Environment_Infrastructure/docker/patroni-postgis
docker build -t registry.iklim.co/infra/patroni-postgis:17-3.5 .
docker push registry.iklim.co/infra/patroni-postgis:17-3.5
```

### 5.2 etcd Kümesi

#### Stack Dosyası — etcd

`/opt/iklimco/stacks/prod-db-etcd.yml`:

```yaml
version: "3.8"

networks:
  iklimco-net:
    external: true

services:
  etcd-01:
    image: bitnami/etcd:3
    environment:
      ALLOW_NONE_AUTHENTICATION: "yes"
      ETCD_NAME: etcd-01
      ETCD_INITIAL_ADVERTISE_PEER_URLS: http://10.20.20.11:2380
      ETCD_LISTEN_PEER_URLS: http://0.0.0.0:2380
      ETCD_ADVERTISE_CLIENT_URLS: http://10.20.20.11:2379
      ETCD_LISTEN_CLIENT_URLS: http://0.0.0.0:2379
      ETCD_INITIAL_CLUSTER: "etcd-01=http://10.20.20.11:2380,etcd-02=http://10.20.20.12:2380,etcd-03=http://10.20.20.13:2380"
      ETCD_INITIAL_CLUSTER_STATE: new
      ETCD_INITIAL_CLUSTER_TOKEN: iklimco-etcd-prod
    volumes:
      - /mnt/storagebox/prod/db/etcd-01/data:/bitnami/etcd/data
    networks:
      - iklimco-net
    ports:
      - target: 2379
        published: 2379
        protocol: tcp
        mode: host
      - target: 2380
        published: 2380
        protocol: tcp
        mode: host
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-01
      restart_policy:
        condition: on-failure

  etcd-02:
    image: bitnami/etcd:3
    environment:
      ALLOW_NONE_AUTHENTICATION: "yes"
      ETCD_NAME: etcd-02
      ETCD_INITIAL_ADVERTISE_PEER_URLS: http://10.20.20.12:2380
      ETCD_LISTEN_PEER_URLS: http://0.0.0.0:2380
      ETCD_ADVERTISE_CLIENT_URLS: http://10.20.20.12:2379
      ETCD_LISTEN_CLIENT_URLS: http://0.0.0.0:2379
      ETCD_INITIAL_CLUSTER: "etcd-01=http://10.20.20.11:2380,etcd-02=http://10.20.20.12:2380,etcd-03=http://10.20.20.13:2380"
      ETCD_INITIAL_CLUSTER_STATE: new
      ETCD_INITIAL_CLUSTER_TOKEN: iklimco-etcd-prod
    volumes:
      - /mnt/storagebox/prod/db/etcd-02/data:/bitnami/etcd/data
    networks:
      - iklimco-net
    ports:
      - target: 2379
        published: 2379
        protocol: tcp
        mode: host
      - target: 2380
        published: 2380
        protocol: tcp
        mode: host
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-02
      restart_policy:
        condition: on-failure

  etcd-03:
    image: bitnami/etcd:3
    environment:
      ALLOW_NONE_AUTHENTICATION: "yes"
      ETCD_NAME: etcd-03
      ETCD_INITIAL_ADVERTISE_PEER_URLS: http://10.20.20.13:2380
      ETCD_LISTEN_PEER_URLS: http://0.0.0.0:2380
      ETCD_ADVERTISE_CLIENT_URLS: http://10.20.20.13:2379
      ETCD_LISTEN_CLIENT_URLS: http://0.0.0.0:2379
      ETCD_INITIAL_CLUSTER: "etcd-01=http://10.20.20.11:2380,etcd-02=http://10.20.20.12:2380,etcd-03=http://10.20.20.13:2380"
      ETCD_INITIAL_CLUSTER_STATE: new
      ETCD_INITIAL_CLUSTER_TOKEN: iklimco-etcd-prod
    volumes:
      - /mnt/storagebox/prod/db/etcd-03/data:/bitnami/etcd/data
    networks:
      - iklimco-net
    ports:
      - target: 2379
        published: 2379
        protocol: tcp
        mode: host
      - target: 2380
        published: 2380
        protocol: tcp
        mode: host
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-03
      restart_policy:
        condition: on-failure
```

**Önemli:** etcd cluster ilk kez başlatılırken üç node aynı anda `ETCD_INITIAL_CLUSTER_STATE: new` ile deploy edilmelidir. Cluster kurulduktan sonra bu değer `existing` olarak güncellenmeli ve stack yeniden deploy edilmelidir (node yeniden başlasın diye `new` kalmamalı; aksi hâlde data dizini sıfırlanır).

### 5.3 Patroni Konfigürasyonu

Her node için ayrı bir `patroni.yml` dosyası oluşturulur. Farklılıklar yalnızca `name` ve `connect_address` alanlarındadır.

**Node 01** — `/mnt/storagebox/prod/db/postgresql-01/config/patroni.yml`:

```yaml
scope: iklim-postgres
namespace: /db/
name: postgresql-01

restapi:
  listen: 0.0.0.0:8008
  connect_address: 10.20.20.11:8008

etcd3:
  hosts:
    - 10.20.20.11:2379
    - 10.20.20.12:2379
    - 10.20.20.13:2379

bootstrap:
  dcs:
    ttl: 30
    loop_wait: 10
    retry_timeout: 10
    maximum_lag_on_failover: 1048576
    postgresql:
      use_pg_rewind: true
      parameters:
        wal_level: replica
        hot_standby: "on"
        wal_keep_size: 512
        max_wal_senders: 5
        max_replication_slots: 5

  initdb:
    - encoding: UTF8
    - data-checksums

  pg_hba:
    - host replication replicator 10.20.20.0/24 scram-sha-256
    - host all all 10.20.10.0/24 scram-sha-256
    - host all all 10.20.20.0/24 scram-sha-256

  users:
    postgres:
      password: "${POSTGRES_PASSWORD}"
      options:
        - superuser

postgresql:
  listen: 0.0.0.0:5432
  connect_address: 10.20.20.11:5432
  data_dir: /var/lib/postgresql/data/pgdata
  pgpass: /tmp/pgpass0
  authentication:
    replication:
      username: replicator
      password: "${REPLICATOR_PASSWORD}"
    superuser:
      username: postgres
      password: "${POSTGRES_PASSWORD}"
  parameters:
    unix_socket_directories: "/var/run/postgresql"

tags:
  nofailover: false
  noloadbalance: false
  clonefrom: false
  nosync: false
```

**Node 02** — `/mnt/storagebox/prod/db/postgresql-02/config/patroni.yml`:

Node 01 ile aynı içerik, yalnızca şu alanlar farklı:

```yaml
name: postgresql-02

restapi:
  connect_address: 10.20.20.12:8008

postgresql:
  connect_address: 10.20.20.12:5432
  data_dir: /var/lib/postgresql/data/pgdata
```

**Node 03** — `/mnt/storagebox/prod/db/postgresql-03/config/patroni.yml`:

```yaml
name: postgresql-03

restapi:
  connect_address: 10.20.20.13:8008

postgresql:
  connect_address: 10.20.20.13:5432
  data_dir: /var/lib/postgresql/data/pgdata
```

### 5.4 Stack Dosyası — Patroni

`/opt/iklimco/stacks/prod-db-patroni.yml`:

```yaml
version: "3.8"

networks:
  iklimco-net:
    external: true

services:
  patroni-01:
    image: registry.iklim.co/infra/patroni-postgis:17-3.5
    environment:
      DATABASE_POSTGRES_ROOT_USER: "${DATABASE_POSTGRES_ROOT_USER}"
      POSTGRES_PASSWORD: "${POSTGRES_PASSWORD}"
      REPLICATOR_PASSWORD: "${REPLICATOR_PASSWORD}"
      TZ: "Europe/Istanbul"
    volumes:
      - /mnt/storagebox/prod/db/postgresql-01/data:/var/lib/postgresql/data
      - /mnt/storagebox/prod/db/postgresql-01/config/patroni.yml:/etc/patroni/patroni.yml:ro
    networks:
      - iklimco-net
    ports:
      - target: 5432
        published: 5432
        protocol: tcp
        mode: host
      - target: 8008
        published: 8008
        protocol: tcp
        mode: host
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-01
      restart_policy:
        condition: on-failure

  patroni-02:
    image: registry.iklim.co/infra/patroni-postgis:17-3.5
    environment:
      DATABASE_POSTGRES_ROOT_USER: "${DATABASE_POSTGRES_ROOT_USER}"
      POSTGRES_PASSWORD: "${POSTGRES_PASSWORD}"
      REPLICATOR_PASSWORD: "${REPLICATOR_PASSWORD}"
      TZ: "Europe/Istanbul"
    volumes:
      - /mnt/storagebox/prod/db/postgresql-02/data:/var/lib/postgresql/data
      - /mnt/storagebox/prod/db/postgresql-02/config/patroni.yml:/etc/patroni/patroni.yml:ro
    networks:
      - iklimco-net
    ports:
      - target: 5432
        published: 5432
        protocol: tcp
        mode: host
      - target: 8008
        published: 8008
        protocol: tcp
        mode: host
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-02
      restart_policy:
        condition: on-failure

  patroni-03:
    image: registry.iklim.co/infra/patroni-postgis:17-3.5
    environment:
      DATABASE_POSTGRES_ROOT_USER: "${DATABASE_POSTGRES_ROOT_USER}"
      POSTGRES_PASSWORD: "${POSTGRES_PASSWORD}"
      REPLICATOR_PASSWORD: "${REPLICATOR_PASSWORD}"
      TZ: "Europe/Istanbul"
    volumes:
      - /mnt/storagebox/prod/db/postgresql-03/data:/var/lib/postgresql/data
      - /mnt/storagebox/prod/db/postgresql-03/config/patroni.yml:/etc/patroni/patroni.yml:ro
    networks:
      - iklimco-net
    ports:
      - target: 5432
        published: 5432
        protocol: tcp
        mode: host
      - target: 8008
        published: 8008
        protocol: tcp
        mode: host
    deploy:
      replicas: 1
      placement:
        constraints:
          - node.hostname == iklim-db-03
      restart_policy:
        condition: on-failure
```

### 5.5 Durum Kontrolü

```bash
# Herhangi bir DB node'unda:
docker exec -it $(docker ps -q -f name=iklim-patroni_patroni-01) \
  patronictl -c /etc/patroni/patroni.yml list
```

Beklenen çıktı: bir `Leader` ve iki `Replica` satırı, hepsinin `State` sütunu `running`.

```bash
# etcd cluster sağlığı:
docker exec -it $(docker ps -q -f name=iklim-etcd_etcd-01) \
  etcdctl endpoint health \
  --endpoints=http://10.20.20.11:2379,http://10.20.20.12:2379,http://10.20.20.13:2379
```

```bash
# Mevcut primary'i öğren:
docker exec -it $(docker ps -q -f name=iklim-patroni_patroni-01) \
  patronictl -c /etc/patroni/patroni.yml topology
```

## 6. Deploy

Sıra önemlidir: önce etcd, ardından MongoDB ve Patroni stack'leri.

```bash
# iklim-app-01 üzerinde (Swarm manager):
export $(cat /opt/iklimco/stacks/.env | xargs)

# 1. etcd cluster:
docker stack deploy \
  --compose-file /opt/iklimco/stacks/prod-db-etcd.yml \
  --with-registry-auth \
  iklim-etcd

# etcd cluster'ın kurulmasını bekle (yaklaşık 30 saniye):
sleep 30

# etcd sağlığını doğrula:
docker exec -it $(docker ps -q -f name=iklim-etcd_etcd-01) \
  etcdctl endpoint health \
  --endpoints=http://10.20.20.11:2379,http://10.20.20.12:2379,http://10.20.20.13:2379

# 2. MongoDB:
docker stack deploy \
  --compose-file /opt/iklimco/stacks/prod-db-mongo.yml \
  --with-registry-auth \
  iklim-db

# 3. Patroni (PostgreSQL):
docker stack deploy \
  --compose-file /opt/iklimco/stacks/prod-db-patroni.yml \
  --with-registry-auth \
  iklim-patroni

docker stack services iklim-etcd
docker stack services iklim-db
docker stack services iklim-patroni
```

**etcd'yi ikinci kez deploy etmeden önce** `ETCD_INITIAL_CLUSTER_STATE` değerini `new` yerine `existing` olarak güncelle; aksi hâlde veri dizini sıfırlanır. İlk deploy başarılı olduktan sonra `prod-db-etcd.yml` içindeki her serviste bu değeri `existing` yap ve `docker stack deploy` ile güncelle.

### .env Dosyası

`/opt/iklimco/stacks/.env` (repo'ya commit edilmez):

```env
DATABASE_POSTGRES_ROOT_USER=postgres
POSTGRES_PASSWORD=<güçlü-şifre>
REPLICATOR_PASSWORD=<güçlü-şifre>
MONGO_ROOT_PASSWORD=<güçlü-şifre>
```

### MongoDB Replica Set Başlatma

MongoDB stack deploy edildikten sonra bir kez çalıştırılır:

```bash
docker exec -it $(docker ps -q -f name=iklim-db_mongodb-01) mongosh \
  -u mongo-root -p "${MONGO_ROOT_PASSWORD}" --authenticationDatabase admin

# mongosh içinde:
rs.initiate({
  _id: "rs0",
  members: [
    { _id: 0, host: "10.20.20.11:27017", priority: 2 },
    { _id: 1, host: "10.20.20.12:27017", priority: 1 },
    { _id: 2, host: "10.20.20.13:27017", priority: 1 }
  ]
})
```

## 7. App Servislerinden Erişim

### MongoDB Replica Set Connection String

```
mongodb://mongo-root:<SIFRE>@10.20.20.11:27017,10.20.20.12:27017,10.20.20.13:27017/<db>?replicaSet=rs0&authSource=admin
```

### PostgreSQL — Patroni

Patroni her an primary olan node'u yönetir. Uygulama katmanı tüm üç IP'yi vererek primary'e yazabilir, secondary'den okuyabilir:

```
# Yazma — sadece primary kabul eder:
jdbc:postgresql://10.20.20.11:5432,10.20.20.12:5432,10.20.20.13:5432/iklimdb?targetServerType=primary

# Okuma (yük dengeleme):
jdbc:postgresql://10.20.20.11:5432,10.20.20.12:5432,10.20.20.13:5432/iklimdb?targetServerType=preferSecondary
```

PostgreSQL JDBC sürücüsü `targetServerType=primary` ile bağlanmaya çalışacağı tüm node'lara bağlanır ve primary olanı otomatik bulur.

### Patroni REST API

Patroni, 8008 portundan HTTP endpoint sunar. Bu endpoint HAProxy veya benzeri bir load balancer ile kullanılarak primary'i otomatik yönlendirme sağlanabilir:

```bash
# Primary kontrolü (HTTP 200 = primary, HTTP 503 = replica):
curl -s http://10.20.20.11:8008/primary
```

## Kabul Kriterleri

- `docker stack services iklim-etcd` — üç servis `1/1`
- `docker stack services iklim-db` — üç MongoDB servisi `1/1`
- `docker stack services iklim-patroni` — üç Patroni servisi `1/1`
- `patronictl list` — 1 `Leader`, 2 `Replica`, hepsi `running`
- `etcdctl endpoint health` — üç endpoint `healthy`
- `rs.status()` — 1 PRIMARY, 2 SECONDARY
- App node'larından MongoDB ve PostgreSQL'e erişim sağlanır
- `5432`, `27017`, `2379`, `2380`, `8008` portları public internet'ten kapalıdır
- Bir DB node yeniden başlatıldığında Patroni otomatik seçim yapar, yeni primary belirlenir
- Patroni primary geçişi sırasında eski primary standby olarak re-join olur (split-brain yoktur)