Cerebro

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Cerebro (Elasticsearch Admin) Sysadmin Cheatsheet

Cerebro is an open-source web administration tool for Elasticsearch clusters, developed by Leonardo Menezes. It is the successor to the deprecated Elasticsearch Kopf plugin. Cerebro provides a visual interface for cluster monitoring, index management, node operations, and REST API queries.

Common use cases / Типичные сценарии: Elasticsearch cluster health monitoring, index management (create, delete, open/close), shard visualization, alias management, template editing, snapshot management, REST API exploration.

Status / Статус: Cerebro is still functional but no longer actively maintained (last release 0.9.4 in 2021). Modern alternatives include Kibana (official Elastic UI with full management), Elasticsearch Head (Chrome extension), ElasticVue (modern Vue.js-based UI), OpenSearch Dashboards (for OpenSearch clusters).

Default port / Порт по умолчанию: 9000/tcp (Cerebro UI)

📚 Table of Contents / Содержание

1. Installation & Configuration
2. Core Management
3. Sysadmin Operations
4. Security
5. Troubleshooting & Tools
6. Logrotate Configuration

1. Installation & Configuration

Install Cerebro / Установка Cerebro

# Download latest release / Скачать последний релиз
RELEASE="0.9.4"
wget "https://github.com/lmenezes/cerebro/releases/download/v${RELEASE}/cerebro-${RELEASE}.tgz"
tar -xzf cerebro-${RELEASE}.tgz
mv cerebro-${RELEASE} /opt/cerebro

Install via Docker / Установка через Docker

# Run Cerebro in Docker / Запустить Cerebro в Docker
docker run -d --name cerebro \
  -p 9000:9000 \
  -e CEREBRO_PORT=9000 \
  lmenezes/cerebro:latest

# Or with custom config / Или с кастомным конфигом
docker run -d --name cerebro \
  -p 9000:9000 \
  -v /etc/cerebro/application.conf:/opt/cerebro/conf/application.conf:ro \
  lmenezes/cerebro:latest

Main Configuration / Основная конфигурация

/opt/cerebro/conf/application.conf

# Server settings / Настройки сервера
play {
  server.http.port = 9000
}

# Elasticsearch cluster connections / Подключения к кластерам Elasticsearch
hosts = [
  {
    host = "http://<ES_HOST_1>:9200"
    name = "Production Cluster"
  },
  {
    host = "http://<ES_HOST_2>:9200"
    name = "Staging Cluster"
  }
]

# Authentication (optional) / Аутентификация (опционально)
auth = {
  type: "basic"
  settings {
    username = "<USER>"
    password = "<PASSWORD>"
  }
}

# LDAP authentication / Аутентификация через LDAP
# auth = {
#   type: "ldap"
#   settings {
#     url = "ldap://<LDAP_HOST>:389"
#     base-dn = "dc=example,dc=com"
#     method = "simple"
#     user-template = "uid=%s,ou=users,dc=example,dc=com"
#   }
# }

Systemd Service / Сервис systemd

/etc/systemd/system/cerebro.service

[Unit]
Description=Cerebro - Elasticsearch Web Admin
After=network.target

[Service]
Type=simple
User=cerebro
Group=cerebro
WorkingDirectory=/opt/cerebro
ExecStart=/opt/cerebro/bin/cerebro -Dconfig.file=/opt/cerebro/conf/application.conf
Restart=always
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

# Create user and set permissions / Создать пользователя и настроить права
useradd -r -s /sbin/nologin cerebro
chown -R cerebro:cerebro /opt/cerebro

# Enable and start / Активировать и запустить
systemctl daemon-reload
systemctl enable --now cerebro

2. Core Management

Web UI Access / Доступ к веб-интерфейсу

http://<HOST>:9000    # Cerebro dashboard / Панель Cerebro

On first access, enter your Elasticsearch cluster URL to connect. / При первом доступе введите URL вашего кластера Elasticsearch.

Cerebro UI Features / Функции интерфейса Cerebro

Useful Elasticsearch API Queries via Cerebro / Полезные запросы через REST-интерфейс

# Cluster health / Здоровье кластера
GET /_cluster/health

# Node stats / Статистика узлов
GET /_nodes/stats

# Index list / Список индексов
GET /_cat/indices?v&s=store.size:desc

# Shard allocation / Распределение шардов
GET /_cat/shards?v&s=store:desc

# Pending tasks / Ожидающие задачи
GET /_cluster/pending_tasks

# Check disk allocation / Проверить распределение дисков
GET /_cat/allocation?v

3. Sysadmin Operations

Service Management / Управление сервисом

systemctl start cerebro      # Start / Запустить
systemctl stop cerebro       # Stop / Остановить
systemctl restart cerebro    # Restart / Перезапустить
systemctl enable cerebro     # Enable on boot / Автозапуск
systemctl status cerebro     # Check status / Проверить статус

Important Paths / Важные пути

JVM Tuning / Настройка JVM

/opt/cerebro/conf/jvm.options or environment variable:

# Set JVM heap size / Установить размер heap JVM
export JAVA_OPTS="-Xms256m -Xmx512m"

# Or in systemd override / Или через переопределение systemd
# /etc/systemd/system/cerebro.service.d/override.conf
# [Service]
# Environment="JAVA_OPTS=-Xms256m -Xmx512m"

Firewall Configuration / Настройка фаервола

# Allow Cerebro port / Разрешить порт Cerebro
firewall-cmd --permanent --add-port=9000/tcp
firewall-cmd --reload

[!TIP] For security, do not expose Cerebro to the public internet. Use a VPN or SSH tunnel. / Не выставляйте Cerebro в публичный интернет. Используйте VPN или SSH-туннель.

4. Security

Authentication Types / Типы аутентификации

Reverse Proxy with TLS / Обратный прокси с TLS

/etc/nginx/conf.d/cerebro.conf

server {
    listen 443 ssl;
    server_name cerebro.<DOMAIN>;

    ssl_certificate     /etc/ssl/certs/cerebro.crt;
    ssl_certificate_key /etc/ssl/private/cerebro.key;

    location / {
        proxy_pass http://127.0.0.1:9000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

[!WARNING] Cerebro has full access to your Elasticsearch cluster. Anyone with Cerebro access can delete indices, change settings, and modify data. / Cerebro имеет полный доступ к кластеру Elasticsearch. Обеспечьте надлежащую защиту.

5. Troubleshooting & Tools

Common Issues / Частые проблемы

1. Cerebro Cannot Connect to Elasticsearch / Cerebro не может подключиться к ES

# Check Elasticsearch connectivity / Проверить подключение к ES
curl -s http://<ES_HOST>:9200/_cluster/health | jq .

# Check Cerebro logs / Проверить логи Cerebro
tail -50 /opt/cerebro/logs/application.log

# Verify network / Проверить сеть
curl -v http://<ES_HOST>:9200

2. Cerebro UI Loads Slowly / Интерфейс Cerebro загружается медленно

# Check JVM heap usage / Проверить использование JVM heap
jcmd $(pgrep -f cerebro) VM.heap_info 2>/dev/null

# Increase JVM heap / Увеличить JVM heap
# Set JAVA_OPTS="-Xms512m -Xmx1g"

3. Cluster Shows Red/Yellow Status / Кластер показывает статус Red/Yellow

This is an Elasticsearch issue, not Cerebro. Use Cerebro's UI to diagnose: / Это проблема Elasticsearch, не Cerebro. Используйте Cerebro для диагностики:

# In Cerebro REST tab / В REST-интерфейсе Cerebro
GET /_cluster/health
GET /_cat/shards?v&h=index,shard,prirep,state,unassigned.reason&s=state
GET /_cluster/allocation/explain

6. Logrotate Configuration

/etc/logrotate.d/cerebro

/opt/cerebro/logs/*.log {
    daily
    rotate 7
    compress
    delaycompress
    missingok
    notifempty
    create 640 cerebro cerebro
}

Documentation Links / Ссылки на документацию

• GitHub Repository: https://github.com/lmenezes/cerebro
• Releases: https://github.com/lmenezes/cerebro/releases
• Docker Hub: https://hub.docker.com/r/lmenezes/cerebro
• Alternative — ElasticVue: https://elasticvue.com/
• Alternative — Kibana: https://www.elastic.co/kibana