性能工具之emqtt_bench快速上手

一、前言

本文主要总结 emqtt_bench 快速上手，让大家对 MQTT消息中间 BenchMark 测试工具有个整体了解，方便平常在性能测试工作查阅。

二、什么是emqtt_bench？

emqtt-bench 是 emqx 编写的用于测试MQTT服务器性能的测试程序，使用 Erlang 语言编写，与其它工具（如：JMeter）相比，emqtt_bench 的优点是安装和使用简单，占用的计算资源较少。但它支持的场景比较有限，需要结合其他监控工具测试指标数据。

三、如何安装？

emqtt-bench 支持 3 种方式来安装：

• Docker 镜像
• 二进制包
• 源代码构建

这里我演示二进制包如何安装：
前往 Releases 页面查看具体的 emqtt-bench 发布版本信息。

emqtt-bench的二进制包支撑的平台：

• Amazon Linux 2
• Amazon Linux 2023
• CentOS 7
• Rocky Linux 8
• Rocky Linux 9
• Debian 9
• Debian 10
• Debian 11
• Debian 12
• Ubuntu 16.04
• Ubuntu 18.04
• Ubuntu 20.04
• Ubuntu 22.04
• MacOS 11 (Intel)
• MacOS 12 (Intel)
• MacOS 12 (Apple Silicon)

这里我以 CentOS 7 为例：

• 工具地址：https://github.com/emqx/emqtt-bench/releases/download/0.4.18/emqtt-bench-0.4.18-el7-amd64.tar.gz
• 版本号：v0.4.18

##创建安装目录
mkdir emqtt-bench && cd emqtt-bench
##在线下载二进制包
wget https://github.com/emqx/emqtt-bench/releases/download/0.4.18/emqtt-bench-0.4.18-el7-amd64.tar.gz
##解压包
tar xfz emqtt-bench-0.4.18-el7-amd64.tar.gz
##删除文件
rm emqtt-bench-0.4.18-el7-amd64.tar.gz

##运行
cd bin/
./emqtt_bench
Usage: emqtt_bench pub | sub | conn [--help]

四、如何使用？

emqtt_bench 共三个子命令：

• pub：用于创建大量客户端执行发布消息的操作。
• sub：用于创建大量客户端执行订阅主题，并接受消息的操作。
• conn：用于创建大量的连接。

1、发布

执行 ./emqtt_bench pub --help 会得到可用的参数输出：

[root@data-server bin]# ./emqtt_bench pub --help
Usage: emqtt_bench pub [--help <help>] [-d <dist>] [-h [<host>]] [-p [<port>]] [-V [<version>]] [-c [<count>]]
                       [-n [<startnumber>]] [-i [<interval>]] [-I [<interval_of_msg>]] [-u <username>] [-P <password>]
                       [-t <topic>] [--payload-hdrs [<payload_hdrs>]] [-s [<size>]] [-m <message>] [-q [<qos>]]
                       [-Q [<qoe>]] [-r [<retain>]] [-k [<keepalive>]] [-C [<clean>]] [--reconnect [<reconnect>]]
                       [-x [<expiry>]] [-L [<limit>]] [-S [<ssl>]] [--certfile <certfile>] [--keyfile <keyfile>]
                       [--ws [<ws>]] [--quic [<quic>]] [--load-qst <nst_dets_file>] [--ifaddr <ifaddr>] [--prefix <prefix>]
                       [-s [<shortids>]] [-l <lowmem>] [-F [<inflight>]] [-w [<wait_before_publishing>]]
                       [--max-random-wait [<max_random_wait>]] [--min-random-wait [<min_random_wait>]]
                       [--num-retry-connect [<num_retry_connect>]] [-R [<conn_rate>]]
                       [--force-major-gc-interval [<force_major_gc_interval>]] [--log_to [<log_to>]]
                       [--retry-interval [<retry_interval>]]

  --help                        help information
  -d, --dist                    enable distribution port
  -h, --host                    mqtt server hostname or comma-separated hostnames [default: localhost]
  -p, --port                    mqtt server port number [default: 1883]
  -V, --version                 mqtt protocol version: 3 | 4 | 5 [default: 5]
  -c, --count                   max count of clients [default: 200]
  -n, --startnumber             The start point when assigning sequence numbers to clients. This is useful when running 
                                multiple emqtt-bench instances to test the same broker (cluster), so the start number can be 
                                planned to avoid client ID collision [default: 0]
  -i, --interval                interval of connecting to the broker [default: 10]
  -I, --interval_of_msg         interval of publishing message(ms) [default: 1000]
  -u, --username                username for connecting to server
  -P, --password                password for connecting to server
  -t, --topic                   topic subscribe, support %u, %c, %i, %s variables
  --payload-hdrs                 If set, add optional payload headers. cnt64: strictly increasing counter(64bit) per 
                                publisher ts: Timestamp when emit example: --payload-hdrs cnt64,ts [default: ]
  -s, --size                    payload size [default: 256]
  -m, --message                 Set the message content for publish. Either a literal message content, or path to a file 
                                with payload template specified via 'template://<file_path>'. Available variables: 
                                %TIMESTAMP%, %TIMESTAMPMS%, %TIMESTAMPUS%, %TIMESTAMPNS%, %UNIQUE%, %RANDOM%. When using 
                                'template://', --size option does not have effect except for when %RANDOM% placeholder is 
                                used.
  -q, --qos                     subscribe qos [default: 0]
  -Q, --qoe                     Enable QoE tracking [default: false]
  -r, --retain                  retain message [default: false]
  -k, --keepalive               keep alive in seconds [default: 300]
  -C, --clean                   clean start [default: true]
  --reconnect                   max retries of reconnects. 0: disabled [default: 0]
  -x, --session-expiry          Set 'Session-Expiry' for persistent sessions (seconds) [default: 0]
  -L, --limit                   The max message count to publish, 0 means unlimited [default: 0]
  -S, --ssl                     ssl socoket for connecting to server [default: false]
  --certfile                    client certificate for authentication, if required by server
  --keyfile                     client private key for authentication, if required by server
  --ws                          websocket transport [default: false]
  --quic                        QUIC transport [default: false]
  --load-qst                    load quic session tickets from dets file
  --ifaddr                      One or multiple (comma-separated) source IP addresses
  --prefix                      Client ID prefix. If not provided '$HOST_bench_(pub|sub)_$RANDOM_$N' is used, where $HOST is 
                                either the host name or the IP address provided in the --ifaddr option, $RANDOM is a random 
                                number and $N is the sequence number assigned for each client. If provided, the $RANDOM 
                                suffix will not be added.
  -s, --shortids                Use short client ID. If --prefix is provided, the prefix is added otherwise client ID is the 
                                assigned sequence number. [default: false]
  -l, --lowmem                  enable low mem mode, but use more CPU
  -F, --inflight                maximum inflight messages for QoS 1 an 2, value 0 for 'infinity' [default: 1]
  -w, --wait-before-publishing  wait for all publishers to have (at least tried to) connected before starting publishing 
                                [default: false]
  --max-random-wait             maximum randomized period in ms that each publisher will wait before starting to publish 
                                (uniform distribution) [default: 0]
  --min-random-wait             minimum randomized period in ms that each publisher will wait before starting to publish 
                                (uniform distribution) [default: 0]
  --num-retry-connect           number of times to retry estabilishing a connection before giving up [default: 0]
  -R, --connrate                connection rate(/s), default: 0, fallback to use --interval [default: 0]
  --force-major-gc-interval     interval in milliseconds in which a major GC will be forced on the bench processes.  a value 
                                of 0 means disabled (default).  this only takes effect when used together with --lowmem. 
                                [default: 0]
  --log_to                      Control where the log output goes. console: directly to the console      null: quietly, 
                                don't output any logs. [default: console]
  --retry-interval              Publisher's resend interval (in seconds) if the expected acknowledgement for a inflight 
                                packet is not received within this interval. Default value 0 means no resend. [default: 0]

参数解释如下：

启动 10 个连接，分别每秒向主题 t 发送 100 条 Qos0 消息，其中每个消息体的大小为 16 字节大小：

./emqtt_bench pub -t t -h emqx-server -s 16 -q 0 -c 10 -I 10

客户端截图：

服务端截图：

2、订阅

启动 500 个连接，每个都以 Qos0 订阅 t 主题：

./emqtt_bench sub -t t -h emqx-server -c 500

客户端截图：

服务端截图：

3、连接

建立大量连接，启动 1000 个连接：

./emqtt_bench conn -h emqx-server -c 1000

客户端截图：

服务端截图：

五、总结

MQTT 协议是目前最适合物联网场景数据平台搭建的通信协议。基于此，BenchMark 联网场景中的 MQTT 消息采集与传递，以及如何构建一个百万级，甚至千万级 MQTT 消息平台，可以为物联网业务的企业用户提供平台架构设计参考。

参考资料：

• EMQX官网