| # MongoDB monitoring |
| |
| SkyWalking leverages mongodb-exporter for collecting metrics data from MongoDB. It leverages OpenTelemetry |
| Collector to transfer the metrics to |
| [OpenTelemetry receiver](opentelemetry-receiver.md) and into the [Meter System](./../../concepts-and-designs/mal.md). |
| |
| ## Data flow |
| |
| 1. The `mongodb-exporter` collects metrics data from MongoDB. The exporter works side by side with the MongoDB node. |
| 2. OpenTelemetry Collector fetches metrics from mongodb-exporter via Prometheus Receiver and pushes metrics to |
| SkyWalking OAP Server via OpenTelemetry gRPC exporter. |
| 3. The SkyWalking OAP Server parses the expression with [MAL](../../concepts-and-designs/mal.md) to |
| filter/calculate/aggregate and store the results. |
| |
| ## Setup |
| |
| 1. Setup [mongodb-exporter](https://github.com/percona/mongodb_exporter). |
| 2. Set up [OpenTelemetry Collector](https://opentelemetry.io/docs/collector/getting-started/#docker). The example for OpenTelemetry Collector configuration, refer |
| to [here](../../../../test/e2e-v2/cases/mongodb/otel-collector-config.yaml). |
| 3. Config SkyWalking [OpenTelemetry receiver](opentelemetry-receiver.md). |
| |
| ## MongoDB Monitoring |
| |
| MongoDB monitoring provides multidimensional metrics monitoring of MongoDB clusters as `Layer: MONGODB` `Service` in the OAP. In each cluster, the nodes are represented as `Instance`. |
| |
| ### MongoDB Cluster Supported Metrics |
| |
| | Monitoring Panel | Unit | Metric Name | Description | Data Source | |
| |---------------------------|------|-------------------------------------------|---------------------------------------------------------------------|------------------| |
| | Uptime (day) | day | meter_mongodb_cluster_uptime | Maximum uptime of nodes in the cluster | mongodb-exporter | |
| | Data Size (GB) | GB | meter_mongodb_cluster_data_size | Total data size of the cluster | mongodb-exporter | |
| | Collection Count | | meter_mongodb_cluster_collection_count | Number of collection of the cluster | mongodb-exporter | |
| | Object Count | | meter_mongodb_cluster_object_count | Number of object of the cluster | mongodb-exporter | |
| | Document Total QPS | | meter_mongodb_cluster_document_avg_qps | Total document operations rate of nodes | mongodb-exporter | |
| | Operation Total QPS | | meter_mongodb_cluster_operation_avg_qps | Total operations rate of nodes | mongodb-exporter | |
| | Total Connections | | meter_mongodb_cluster_connections | Cluster total connections of nodes | mongodb-exporter | |
| | Cursor Total | | meter_mongodb_cluster_cursor_avg | Total Opened cursor of nodes | mongodb-exporter | |
| | Replication Lag (ms) | ms | meter_mongodb_cluster_repl_lag | Repl set member avg replication lag, this metric works in repl mode | mongodb-exporter | |
| | DB Total Data Size (GB) | GB | meter_mongodb_cluster_db_data_size | Total data size of every database | mongodb-exporter | |
| | DB Total Index Size (GB) | GB | meter_mongodb_cluster_db_index_size | Total index size per of every database | mongodb-exporter | |
| | DB Total Collection Count | | meter_mongodb_cluster_db_collection_count | Total collection count of every database | mongodb-exporter | |
| | DB Total Index Count | | meter_mongodb_cluster_db_index_count | Total index count of every database | mongodb-exporter | |
| |
| ### MongoDB Node Supported Metrics |
| |
| | Monitoring Panel | Unit | Metric Name | Description | Data Source | |
| |------------------------------|------|-----------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------|------------------| |
| | Uptime (day) | day | meter_mongodb_node_uptime | Uptime of the node | mongodb-exporter | |
| | QPS | | meter_mongodb_node_qps | Operations per second of the node | mongodb-exporter | |
| | Latency | µs | meter_mongodb_node_op_rate<br/>meter_mongodb_node_latency_rate | Latency of operations | mongodb-exporter | |
| | Memory Usage | % | meter_mongodb_node_memory_usage | Memory usage percent of RAM | mongodb-exporter | |
| | Version | | meter_mongodb_node_version | MongoDB edition and version | mongodb-exporter | |
| | ReplSet State | | meter_mongodb_node_rs_state | Repl set state of the node, this metric works in repl mode | mongodb-exporter | |
| | CPU Usage (%) | % | meter_mongodb_node_cpu_total_percentage | Cpu usage percent of the node | mongodb-exporter | |
| | Network (KB/s) | KB/s | meter_mongodb_node_network_bytes_in<br/>meter_mongodb_node_network_bytes_out | Inbound and outbound network bytes of node | mongodb-exporter | |
| | Memory Free (GB) | GB | meter_mongodb_node_memory_free_kb<br/>meter_mongodb_node_swap_memory_free_kb | Free memory of RAM and swap | mongodb-exporter | |
| | Disk (GB) | GB | meter_mongodb_node_fs_used_size<br/>meter_mongodb_node_fs_total_size | Used and total size of disk | mongodb-exporter | |
| | Connections | | meter_mongodb_node_connections | Connection nums of node | mongodb-exporter | |
| | Active Client | | meter_mongodb_node_active_total_num<br/>meter_mongodb_node_active_reader_num<br/>meter_mongodb_node_active_writer_num | Count of active reader and writer | mongodb-exporter | |
| | Transactions | | meter_mongodb_node_transactions_active<br/>meter_mongodb_node_transactions_inactive | Count of transactions running on the node | mongodb-exporter | |
| | Document QPS | | meter_mongodb_node_document_qps | Document operations per second | mongodb-exporter | |
| | Operation QPS | | meter_mongodb_node_operation_qps | Operations per second | mongodb-exporter | |
| | Repl Operation QPS | | meter_mongodb_node_repl_operation_qps | Repl operations per second | mongodb-exporter | |
| | Operation Latency (µs) | µs | meter_mongodb_node_op_rate<br/>meter_mongodb_node_latency_rate | Latencies for different operation type | mongodb-exporter | |
| | Cursor | | meter_mongodb_node_cursor | Opened cursor of the node | mongodb-exporter | |
| | Server Status Memory (MB) | MB | meter_mongodb_node_mem_virtual<br/>meter_mongodb_node_mem_resident | Virtual and resident memory of the node | mongodb-exporter | |
| | Asserts | | meter_mongodb_node_asserts | The rate of raised assertions | mongodb-exporter | |
| | Repl Buffer Count | | meter_mongodb_node_repl_buffer_count | The current number of operations in the oplog buffer | mongodb-exporter | |
| | Repl Buffer Size (MB) | MB | meter_mongodb_node_repl_buffer_size<br/>meter_mongodb_node_repl_buffer_size_max | The maximum size of the oplog buffer | mongodb-exporter | |
| | Queued Operation | | meter_mongodb_node_queued_operation | The number of operations queued because of a lock | mongodb-exporter | |
| | getLastError Write Num | | meter_mongodb_node_write_wait_num<br/>meter_mongodb_node_write_wait_timeout_num | The number of write concern operation | mongodb-exporter | |
| | getLastError Write Time (ms) | ms | meter_mongodb_node_write_wait_time | The wait time of write concern operation | mongodb-exporter | |
| |
| ## Customizations |
| |
| You can customize your own metrics/expression/dashboard panel. |
| The metrics definition and expression rules are found |
| in `/config/otel-rules/mongodb/mongodb-cluster.yaml, /config/otel-rules/mongodb/mongodb-node.yaml`. |
| The MongoDB dashboard panel configurations are found in `/config/ui-initialized-templates/mongodb`. |
