skywalking是什么？
Skywalking 是一个分布式追踪（Trace）系统。除了 Skywalking 之外，比较出名的分布式追踪系统还有 Dapper、鹰眼、Pinpoint 、Zipkin等等。
skywalking 架构
springboot项目如何集成skywalking
首先搭建环境
1.linux系统（安装jdk）这个就不多说了
配置linux需要的环境
内存 3G， 处理器数量 2 （提高下性能）
1.1 修改系统限制配置
vi /etc/security/limits.conf
//新增下面内容
es soft nofile 65536
es hard nofile 65546
es soft nproc 4096
es hard nproc 4096
1.2
vi /etc/sysctl.conf
vm.max_map_count=262144
修改完执行下面生效
sysctl -p
2.准备阶段
apache-skywalking-apm-7.0.0.tar.gz
elasticsearch-6.2.2.tar.gz
启动elasticsearch-6.2.2（简单，无需过多配置）
修改skywalking配置
修改webapp/webapp.yml 端口改个 skywalking web页面的端口
修改agent中config/agent.config
修改agent.service_name=${SW_AGENT_NAME:skywalking_boot}
skywalking_boot 自己取个名字（好像没啥用）
修改apache-skywalking-apm-bin目录下的 /config/application.yml
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_SW_STORAGE_ES_SSL_JKS_PATH:"../es_keystore.jks"}
trustStorePass: ${SW_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.
enablePackedDownsampling: ${SW_STORAGE_ENABLE_PACKED_DOWNSAMPLING:true} # Hour and Day metrics will be merged into minute index.
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:2}
indexReplicasNumber: ${SW_STORAGE_ES_INDEX_REPLICAS_NUMBER:0}
# Those data TTL settings will override the same settings in core module.
recordDataTTL: ${SW_STORAGE_ES_RECORD_DATA_TTL:7} # Unit is day
otherMetricsDataTTL: ${SW_STORAGE_ES_OTHER_METRIC_DATA_TTL:45} # Unit is day
monthMetricsDataTTL: ${SW_STORAGE_ES_MONTH_METRIC_DATA_TTL:18} # Unit is month
# 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:1000} # Execute the bulk every 1000 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: ${SW_STORAGE_ES_QUERY_PROFILE_TASK_SIZE:200}
默认：selector ：${SW_STORAGE:h2}
修改成 selector ：${SW_STORAGE:elasticsearch}
最后把项目打成jar包 上传到linux
然后通过命令
java -javaagent:/usr/local/skywalking/apache-skywalking-apm-bin/agent/skywalking-agent.jar -jardistributed-security-eureka.jar &
让skywalking 探针获取项目的数据
