Backend storage

SkyWalking storage is pluggable, we have provided the following storage solutions, you could easily use one of them by specifying it as the selector in the application.yml

storage:
  selector: ${SW_STORAGE:elasticsearch7}

Native supported storage

  • H2
  • OpenSearch
  • ElasticSearch 6, 7
  • MySQL
  • TiDB
  • InfluxDB
  • PostgreSQL

H2

Active H2 as storage, set storage provider to H2 In-Memory Databases. Default in distribution package. Please read Database URL Overview in H2 official document, you could set the target to H2 in Embedded, Server and Mixed modes.

Setting fragment example

storage:
  selector: ${SW_STORAGE:h2}
  h2:
    driver: org.h2.jdbcx.JdbcDataSource
    url: jdbc:h2:mem:skywalking-oap-db
    user: sa

OpenSearch

OpenSearch storage shares the same configurations as ElasticSearch 7. In order to activate ElasticSearch 7 as storage, set storage provider to elasticsearch7. Please download the apache-skywalking-bin-es7.tar.gz if you want to use OpenSearch as storage.

ElasticSearch

NOTICE: Elastic announced through their blog that Elasticsearch will be moving over to a Server Side Public License (SSPL), which is incompatible with Apache License 2.0. This license change is effective from Elasticsearch version 7.11. So please choose the suitable ElasticSearch version according to your usage.

  • In order to activate ElasticSearch 6 as storage, set storage provider to elasticsearch
  • In order to activate ElasticSearch 7 as storage, set storage provider to elasticsearch7

Required ElasticSearch 6.3.2 or higher. HTTP RestHighLevelClient is used to connect server.

  • For ElasticSearch 6.3.2 ~ 7.0.0 (excluded), please download the apache-skywalking-bin.tar.gz,
  • For ElasticSearch 7.0.0 ~ 8.0.0 (excluded), please download the apache-skywalking-bin-es7.tar.gz.

For now, ElasticSearch 6 and ElasticSearch 7 share the same configurations, as follows:

storage:
  selector: ${SW_STORAGE:elasticsearch}
  elasticsearch:
    nameSpace: ${SW_NAMESPACE:""}
    clusterNodes: ${SW_STORAGE_ES_CLUSTER_NODES:localhost:9200}
    protocol: ${SW_STORAGE_ES_HTTP_PROTOCOL:"http"}
    trustStorePath: ${SW_STORAGE_ES_SSL_JKS_PATH:""}
    trustStorePass: ${SW_STORAGE_ES_SSL_JKS_PASS:""}
    user: ${SW_ES_USER:""}
    password: ${SW_ES_PASSWORD:""}
    secretsManagementFile: ${SW_ES_SECRETS_MANAGEMENT_FILE:""} # Secrets management file in the properties format includes the username, password, which are managed by 3rd party tool.
    dayStep: ${SW_STORAGE_DAY_STEP:1} # Represent the number of days in the one minute/hour/day index.
    indexShardsNumber: ${SW_STORAGE_ES_INDEX_SHARDS_NUMBER:1} # Shard number of new indexes
    indexReplicasNumber: ${SW_STORAGE_ES_INDEX_REPLICAS_NUMBER:1} # Replicas number of new indexes
    # Super data set has been defined in the codes, such as trace segments.The following 3 config would be improve es performance when storage super size data in es.
    superDatasetDayStep: ${SW_SUPERDATASET_STORAGE_DAY_STEP:-1} # Represent the number of days in the super size dataset record index, the default value is the same as dayStep when the value is less than 0
    superDatasetIndexShardsFactor: ${SW_STORAGE_ES_SUPER_DATASET_INDEX_SHARDS_FACTOR:5} #  This factor provides more shards for the super data set, shards number = indexShardsNumber * superDatasetIndexShardsFactor. Also, this factor effects Zipkin and Jaeger traces.
    superDatasetIndexReplicasNumber: ${SW_STORAGE_ES_SUPER_DATASET_INDEX_REPLICAS_NUMBER:0} # Represent the replicas number in the super size dataset record index, the default value is 0.
    indexTemplateOrder: ${SW_STORAGE_ES_INDEX_TEMPLATE_ORDER:0} # the order of index template
    bulkActions: ${SW_STORAGE_ES_BULK_ACTIONS:1000} # Execute the async bulk record data every ${SW_STORAGE_ES_BULK_ACTIONS} requests
    flushInterval: ${SW_STORAGE_ES_FLUSH_INTERVAL:10} # flush the bulk every 10 seconds whatever the number of requests
    concurrentRequests: ${SW_STORAGE_ES_CONCURRENT_REQUESTS:2} # the number of concurrent requests
    resultWindowMaxSize: ${SW_STORAGE_ES_QUERY_MAX_WINDOW_SIZE:10000}
    metadataQueryMaxSize: ${SW_STORAGE_ES_QUERY_MAX_SIZE:5000}
    segmentQueryMaxSize: ${SW_STORAGE_ES_QUERY_SEGMENT_SIZE:200}
    profileTaskQueryMaxSize: ${SW_STORAGE_ES_QUERY_PROFILE_TASK_SIZE:200}
    oapAnalyzer: ${SW_STORAGE_ES_OAP_ANALYZER:"{\"analyzer\":{\"oap_analyzer\":{\"type\":\"stop\"}}}"} # the oap analyzer.
    oapLogAnalyzer: ${SW_STORAGE_ES_OAP_LOG_ANALYZER:"{\"analyzer\":{\"oap_log_analyzer\":{\"type\":\"standard\"}}}"} # the oap log analyzer. It could be customized by the ES analyzer configuration to support more language log formats, such as Chinese log, Japanese log and etc.
    advanced: ${SW_STORAGE_ES_ADVANCED:""}

ElasticSearch 6 With Https SSL Encrypting communications.

example:

storage:
  selector: ${SW_STORAGE:elasticsearch}
  elasticsearch:
    # nameSpace: ${SW_NAMESPACE:""}
    user: ${SW_ES_USER:""} # User needs to be set when Http Basic authentication is enabled
    password: ${SW_ES_PASSWORD:""} # Password to be set when Http Basic authentication is enabled
    clusterNodes: ${SW_STORAGE_ES_CLUSTER_NODES:localhost:443}
    trustStorePath: ${SW_SW_STORAGE_ES_SSL_JKS_PATH:"../es_keystore.jks"}
    trustStorePass: ${SW_SW_STORAGE_ES_SSL_JKS_PASS:""}
    protocol: ${SW_STORAGE_ES_HTTP_PROTOCOL:"https"}
    ...

Daily Index Step

Daily index step(storage/elasticsearch/dayStep, default 1) represents the index creation period. In this period, several days(dayStep value)' metrics are saved.

Mostly, users don’t need to change the value manually. As SkyWalking is designed to observe large scale distributed system. But in some specific cases, users want to set a long TTL value, such as more than 60 days, but their ElasticSearch cluster isn’t powerful due to the low traffic in the production environment. This value could be increased to 5(or more), if users could make sure single one index could support these days(5 in this case) metrics and traces.

Such as, if dayStep == 11,

  1. data in [2000-01-01, 2000-01-11] will be merged into the index-20000101.
  2. data in [2000-01-12, 2000-01-22] will be merged into the index-20000112.

storage/elasticsearch/superDatasetDayStep override the storage/elasticsearch/dayStep if the value is positive. This would affect the record related entities, such as the trace segment. In some cases, the size of metrics is much less than the record(trace), this would help the shards balance in the ElasticSearch cluster.

NOTICE, TTL deletion would be affected by these. You should set an extra more dayStep in your TTL. Such as you want to TTL == 30 days and dayStep == 10, you actually need to set TTL = 40;

Secrets Management File Of ElasticSearch Authentication

The value of secretsManagementFile should point to the secrets management file absolute path. The file includes username, password and JKS password of ElasticSearch server in the properties format.

user=xxx
password=yyy
trustStorePass=zzz

The major difference between using user, password, trustStorePass configs in the application.yaml file is, the Secrets Management File is being watched by the OAP server. Once it is changed manually or through 3rd party tool, such as Vault, the storage provider will use the new username, password and JKS password to establish the connection and close the old one. If the information exist in the file, the user/password will be overrided.

Advanced Configurations For Elasticsearch Index

You can add advanced configurations in JSON format to set ElasticSearch index settings by following ElasticSearch doc

For example, set translog settings:

storage:
  elasticsearch:
    # ......
    advanced: ${SW_STORAGE_ES_ADVANCED:"{\"index.translog.durability\":\"request\",\"index.translog.sync_interval\":\"5s\"}"}

You could add following config to elasticsearch.yml, set the value based on your env.

# In tracing scenario, consider to set more than this at least.
thread_pool.index.queue_size: 1000 # Only suitable for ElasticSearch 6
thread_pool.write.queue_size: 1000 # Suitable for ElasticSearch 6 and 7

# When you face query error at trace page, remember to check this.
index.max_result_window: 1000000

We strongly advice you to read more about these configurations from ElasticSearch official document. This effects the performance of ElasticSearch very much.

ElasticSearch 7 with Zipkin trace extension

This implementation shares most of elasticsearch7, just extends to support zipkin span storage. It has all same configs.

storage:
  selector: ${SW_STORAGE:zipkin-elasticsearch7}
  zipkin-elasticsearch7:
    nameSpace: ${SW_NAMESPACE:""}
    clusterNodes: ${SW_STORAGE_ES_CLUSTER_NODES:localhost:9200}
    protocol: ${SW_STORAGE_ES_HTTP_PROTOCOL:"http"}
    user: ${SW_ES_USER:""}
    password: ${SW_ES_PASSWORD:""}
    indexShardsNumber: ${SW_STORAGE_ES_INDEX_SHARDS_NUMBER:2}
    indexReplicasNumber: ${SW_STORAGE_ES_INDEX_REPLICAS_NUMBER:0}
    # Batch process setting, refer to https://www.elastic.co/guide/en/elasticsearch/client/java-api/5.5/java-docs-bulk-processor.html
    bulkActions: ${SW_STORAGE_ES_BULK_ACTIONS:2000} # Execute the bulk every 2000 requests
    bulkSize: ${SW_STORAGE_ES_BULK_SIZE:20} # flush the bulk every 20mb
    flushInterval: ${SW_STORAGE_ES_FLUSH_INTERVAL:10} # flush the bulk every 10 seconds whatever the number of requests
    concurrentRequests: ${SW_STORAGE_ES_CONCURRENT_REQUESTS:2} # the number of concurrent requests

About Namespace

When namespace is set, names of all indexes in ElasticSearch will use it as prefix.

MySQL

Active MySQL as storage, set storage provider to mysql.

NOTICE: MySQL driver is NOT allowed in Apache official distribution and source codes. Please download MySQL driver by yourself. Copy the connection driver jar to oap-libs.

storage:
  selector: ${SW_STORAGE:mysql}
  mysql:
    properties:
      jdbcUrl: ${SW_JDBC_URL:"jdbc:mysql://localhost:3306/swtest"}
      dataSource.user: ${SW_DATA_SOURCE_USER:root}
      dataSource.password: ${SW_DATA_SOURCE_PASSWORD:root@1234}
      dataSource.cachePrepStmts: ${SW_DATA_SOURCE_CACHE_PREP_STMTS:true}
      dataSource.prepStmtCacheSize: ${SW_DATA_SOURCE_PREP_STMT_CACHE_SQL_SIZE:250}
      dataSource.prepStmtCacheSqlLimit: ${SW_DATA_SOURCE_PREP_STMT_CACHE_SQL_LIMIT:2048}
      dataSource.useServerPrepStmts: ${SW_DATA_SOURCE_USE_SERVER_PREP_STMTS:true}
    metadataQueryMaxSize: ${SW_STORAGE_MYSQL_QUERY_MAX_SIZE:5000}

All connection related settings including link url, username and password are in application.yml. Here are some of the settings, please follow HikariCP connection pool document for all the settings.

TiDB

Tested TiDB Server 4.0.8 version and Mysql Client driver 8.0.13 version currently. Active TiDB as storage, set storage provider to tidb.

storage:
  selector: ${SW_STORAGE:tidb}
  tidb:
    properties:
      jdbcUrl: ${SW_JDBC_URL:"jdbc:mysql://localhost:4000/swtest"}
      dataSource.user: ${SW_DATA_SOURCE_USER:root}
      dataSource.password: ${SW_DATA_SOURCE_PASSWORD:""}
      dataSource.cachePrepStmts: ${SW_DATA_SOURCE_CACHE_PREP_STMTS:true}
      dataSource.prepStmtCacheSize: ${SW_DATA_SOURCE_PREP_STMT_CACHE_SQL_SIZE:250}
      dataSource.prepStmtCacheSqlLimit: ${SW_DATA_SOURCE_PREP_STMT_CACHE_SQL_LIMIT:2048}
      dataSource.useServerPrepStmts: ${SW_DATA_SOURCE_USE_SERVER_PREP_STMTS:true}
      dataSource.useAffectedRows: ${SW_DATA_SOURCE_USE_AFFECTED_ROWS:true}
    metadataQueryMaxSize: ${SW_STORAGE_MYSQL_QUERY_MAX_SIZE:5000}
    maxSizeOfArrayColumn: ${SW_STORAGE_MAX_SIZE_OF_ARRAY_COLUMN:20}
    numOfSearchableValuesPerTag: ${SW_STORAGE_NUM_OF_SEARCHABLE_VALUES_PER_TAG:2}

All connection related settings including link url, username and password are in application.yml. These settings can refer to the configuration of MySQL above.

InfluxDB

InfluxDB storage provides a time-series database as a new storage option.

storage:
  selector: ${SW_STORAGE:influxdb}
  influxdb:
    url: ${SW_STORAGE_INFLUXDB_URL:http://localhost:8086}
    user: ${SW_STORAGE_INFLUXDB_USER:root}
    password: ${SW_STORAGE_INFLUXDB_PASSWORD:}
    database: ${SW_STORAGE_INFLUXDB_DATABASE:skywalking}
    actions: ${SW_STORAGE_INFLUXDB_ACTIONS:1000} # the number of actions to collect
    duration: ${SW_STORAGE_INFLUXDB_DURATION:1000} # the time to wait at most (milliseconds)
    fetchTaskLogMaxSize: ${SW_STORAGE_INFLUXDB_FETCH_TASK_LOG_MAX_SIZE:5000} # the max number of fetch task log in a request

All connection related settings including link url, username and password are in application.yml. The Metadata storage provider settings can refer to the configuration of H2/MySQL above.

PostgreSQL

PostgreSQL jdbc driver uses version 42.2.18, it supports PostgreSQL 8.2 or newer. Active PostgreSQL as storage, set storage provider to postgresql.

storage:
  selector: ${SW_STORAGE:postgresql}
  postgresql:
    properties:
      jdbcUrl: ${SW_JDBC_URL:"jdbc:postgresql://localhost:5432/skywalking"}
      dataSource.user: ${SW_DATA_SOURCE_USER:postgres}
      dataSource.password: ${SW_DATA_SOURCE_PASSWORD:123456}
      dataSource.cachePrepStmts: ${SW_DATA_SOURCE_CACHE_PREP_STMTS:true}
      dataSource.prepStmtCacheSize: ${SW_DATA_SOURCE_PREP_STMT_CACHE_SQL_SIZE:250}
      dataSource.prepStmtCacheSqlLimit: ${SW_DATA_SOURCE_PREP_STMT_CACHE_SQL_LIMIT:2048}
      dataSource.useServerPrepStmts: ${SW_DATA_SOURCE_USE_SERVER_PREP_STMTS:true}
    metadataQueryMaxSize: ${SW_STORAGE_MYSQL_QUERY_MAX_SIZE:5000}
    maxSizeOfArrayColumn: ${SW_STORAGE_MAX_SIZE_OF_ARRAY_COLUMN:20}
    numOfSearchableValuesPerTag: ${SW_STORAGE_NUM_OF_SEARCHABLE_VALUES_PER_TAG:2}

All connection related settings including link url, username and password are in application.yml. Here are some of the settings, please follow HikariCP connection pool document for all the settings.

More storage solution extension

Follow Storage extension development guide in Project Extensions document in development guide.