如何使用卡夫卡出口商码头形象？

Question

我试图使用由Bitnami，https://github.com/bitnami/bitnami-docker-kafka-exporter包装的卡夫卡出口商，以及卡夫卡，https://github.com/bitnami/bitnami-docker-kafka的Bitnami图像。我正在尝试运行以下docker-compose.yml

version: '2'

networks:
  app-tier:
    driver: bridge

services:
  zookeeper:
    image: 'bitnami/zookeeper:latest'
    environment:
      - 'ALLOW_ANONYMOUS_LOGIN=yes'
    networks:
      - app-tier
  kafka:
    image: 'bitnami/kafka:latest'
    environment:
      - KAFKA_CFG_ZOOKEEPER_CONNECT=zookeeper:2181
      - ALLOW_PLAINTEXT_LISTENER=yes
    networks:
      - app-tier
  kafka-exporter:
    image: bitnami/kafka-exporter:latest
    ports:
      - "9308:9308"
    command:
      - --kafka.server=kafka:9092

但是，如果我使用docker-compose up运行这个程序，则会得到以下错误：

bitnami-docker-kafka-kafka-exporter-1  | F0103 17:44:12.545739       1 kafka_exporter.go:865] Error Init Kafka Client: kafka: client has run out of available brokers to talk to (Is your cluster reachable?)

我尝试使用如何在docker-compose.yml中将参数传递给入口点的答案来为kafka-exporter服务指定一个command，假设入口点是以exec形式定义的，应该在Docker二进制文件的调用中附加额外的标志。然而，似乎要么kafka:9092的值不适合kafka.server标志的值，要么标志没有被拾取，或者可能存在某种种族条件，出口商在卡夫卡启动和运行之前就失败并退出。对于如何让这个例子起作用，有什么想法吗？

Answer 1

这似乎是由于卡夫卡出口商在卡夫卡开始之前就试图连接到卡夫卡的种族状况造成的。如果我只运行docker-compose up并允许Kafka出口商失败，然后单独运行danielqsh/kafka-exporter容器，它就能工作：

> docker run -it -p 9308:9308 --network bitnami-docker-kafka_app-tier danielqsj/kafka-exporter
I0103 18:49:04.694898       1 kafka_exporter.go:774] Starting kafka_exporter (version=1.4.2, branch=HEAD, revision=15e4ad6a9ea8203135d4b974e825f22e31c750e5)
I0103 18:49:04.703058       1 kafka_exporter.go:934] Listening on HTTP :9308

在http://localhost:9308上，我可以看到度量标准：

# HELP go_gc_duration_seconds A summary of the pause duration of garbage collection cycles.
# TYPE go_gc_duration_seconds summary
go_gc_duration_seconds{quantile="0"} 8.82e-05
go_gc_duration_seconds{quantile="0.25"} 8.82e-05
go_gc_duration_seconds{quantile="0.5"} 8.82e-05
go_gc_duration_seconds{quantile="0.75"} 8.82e-05
go_gc_duration_seconds{quantile="1"} 8.82e-05
go_gc_duration_seconds_sum 8.82e-05
go_gc_duration_seconds_count 1
# HELP go_goroutines Number of goroutines that currently exist.
# TYPE go_goroutines gauge
go_goroutines 20
# HELP go_info Information about the Go environment.
# TYPE go_info gauge
go_info{version="go1.17.3"} 1
# HELP go_memstats_alloc_bytes Number of bytes allocated and still in use.
# TYPE go_memstats_alloc_bytes gauge
go_memstats_alloc_bytes 3.546384e+06
# HELP go_memstats_alloc_bytes_total Total number of bytes allocated, even if freed.
# TYPE go_memstats_alloc_bytes_total counter
go_memstats_alloc_bytes_total 4.492048e+06
# HELP go_memstats_buck_hash_sys_bytes Number of bytes used by the profiling bucket hash table.
# TYPE go_memstats_buck_hash_sys_bytes gauge
go_memstats_buck_hash_sys_bytes 1.448119e+06
# HELP go_memstats_frees_total Total number of frees.
# TYPE go_memstats_frees_total counter
go_memstats_frees_total 6512
# HELP go_memstats_gc_cpu_fraction The fraction of this program's available CPU time used by the GC since the program started.
# TYPE go_memstats_gc_cpu_fraction gauge
go_memstats_gc_cpu_fraction 1.6141668631896834e-06
# HELP go_memstats_gc_sys_bytes Number of bytes used for garbage collection system metadata.
# TYPE go_memstats_gc_sys_bytes gauge
go_memstats_gc_sys_bytes 4.835688e+06
# HELP go_memstats_heap_alloc_bytes Number of heap bytes allocated and still in use.
# TYPE go_memstats_heap_alloc_bytes gauge
go_memstats_heap_alloc_bytes 3.546384e+06
# HELP go_memstats_heap_idle_bytes Number of heap bytes waiting to be used.
# TYPE go_memstats_heap_idle_bytes gauge
go_memstats_heap_idle_bytes 2.686976e+06
# HELP go_memstats_heap_inuse_bytes Number of heap bytes that are in use.
# TYPE go_memstats_heap_inuse_bytes gauge
go_memstats_heap_inuse_bytes 5.07904e+06
# HELP go_memstats_heap_objects Number of allocated objects.
# TYPE go_memstats_heap_objects gauge
go_memstats_heap_objects 4687
# HELP go_memstats_heap_released_bytes Number of heap bytes released to OS.
# TYPE go_memstats_heap_released_bytes gauge
go_memstats_heap_released_bytes 1.736704e+06
# HELP go_memstats_heap_sys_bytes Number of heap bytes obtained from system.
# TYPE go_memstats_heap_sys_bytes gauge
go_memstats_heap_sys_bytes 7.766016e+06
# HELP go_memstats_last_gc_time_seconds Number of seconds since 1970 of last garbage collection.
# TYPE go_memstats_last_gc_time_seconds gauge
go_memstats_last_gc_time_seconds 1.6412358823440428e+09
# HELP go_memstats_lookups_total Total number of pointer lookups.
# TYPE go_memstats_lookups_total counter
go_memstats_lookups_total 0
# HELP go_memstats_mallocs_total Total number of mallocs.
# TYPE go_memstats_mallocs_total counter
go_memstats_mallocs_total 11199
# HELP go_memstats_mcache_inuse_bytes Number of bytes in use by mcache structures.
# TYPE go_memstats_mcache_inuse_bytes gauge
go_memstats_mcache_inuse_bytes 9600
# HELP go_memstats_mcache_sys_bytes Number of bytes used for mcache structures obtained from system.
# TYPE go_memstats_mcache_sys_bytes gauge
go_memstats_mcache_sys_bytes 16384
# HELP go_memstats_mspan_inuse_bytes Number of bytes in use by mspan structures.
# TYPE go_memstats_mspan_inuse_bytes gauge
go_memstats_mspan_inuse_bytes 71536
# HELP go_memstats_mspan_sys_bytes Number of bytes used for mspan structures obtained from system.
# TYPE go_memstats_mspan_sys_bytes gauge
go_memstats_mspan_sys_bytes 81920
# HELP go_memstats_next_gc_bytes Number of heap bytes when next garbage collection will take place.
# TYPE go_memstats_next_gc_bytes gauge
go_memstats_next_gc_bytes 5.283728e+06
# HELP go_memstats_other_sys_bytes Number of bytes used for other system allocations.
# TYPE go_memstats_other_sys_bytes gauge
go_memstats_other_sys_bytes 1.499625e+06
# HELP go_memstats_stack_inuse_bytes Number of bytes in use by the stack allocator.
# TYPE go_memstats_stack_inuse_bytes gauge
go_memstats_stack_inuse_bytes 622592
# HELP go_memstats_stack_sys_bytes Number of bytes obtained from system for stack allocator.
# TYPE go_memstats_stack_sys_bytes gauge
go_memstats_stack_sys_bytes 622592
# HELP go_memstats_sys_bytes Number of bytes obtained from system.
# TYPE go_memstats_sys_bytes gauge
go_memstats_sys_bytes 1.6270344e+07
# HELP go_threads Number of OS threads created.
# TYPE go_threads gauge
go_threads 8
# HELP kafka_brokers Number of Brokers in the Kafka Cluster.
# TYPE kafka_brokers gauge
kafka_brokers 1
# HELP kafka_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, and goversion from which kafka_exporter was built.
# TYPE kafka_exporter_build_info gauge
kafka_exporter_build_info{branch="HEAD",goversion="go1.17.3",revision="15e4ad6a9ea8203135d4b974e825f22e31c750e5",version="1.4.2"} 1
# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
# TYPE process_cpu_seconds_total counter
process_cpu_seconds_total 0.11
# HELP process_max_fds Maximum number of open file descriptors.
# TYPE process_max_fds gauge
process_max_fds 1.048576e+06
# HELP process_open_fds Number of open file descriptors.
# TYPE process_open_fds gauge
process_open_fds 12
# HELP process_resident_memory_bytes Resident memory size in bytes.
# TYPE process_resident_memory_bytes gauge
process_resident_memory_bytes 1.703936e+07
# HELP process_start_time_seconds Start time of the process since unix epoch in seconds.
# TYPE process_start_time_seconds gauge
process_start_time_seconds 1.64123574422e+09
# HELP process_virtual_memory_bytes Virtual memory size in bytes.
# TYPE process_virtual_memory_bytes gauge
process_virtual_memory_bytes 7.35379456e+08
# HELP process_virtual_memory_max_bytes Maximum amount of virtual memory available in bytes.
# TYPE process_virtual_memory_max_bytes gauge
process_virtual_memory_max_bytes 1.8446744073709552e+19
# HELP promhttp_metric_handler_requests_in_flight Current number of scrapes being served.
# TYPE promhttp_metric_handler_requests_in_flight gauge
promhttp_metric_handler_requests_in_flight 1
# HELP promhttp_metric_handler_requests_total Total number of scrapes by HTTP status code.
# TYPE promhttp_metric_handler_requests_total counter
promhttp_metric_handler_requests_total{code="200"} 3
promhttp_metric_handler_requests_total{code="500"} 0
promhttp_metric_handler_requests_total{code="503"} 0

更新

一种更可靠的方法是使用包装器脚本来执行https://docs.docker.com/compose/startup-order/中描述的特定于应用程序的健康检查。具有以下目录结构，

.
├── docker-compose.yml
└── kafka-exporter
    ├── Dockerfile
    └── run.sh

下面的Dockerfile，

FROM bitnami/kafka-exporter:latest
COPY run.sh /opt/bitnami/kafka-exporter/bin

ENTRYPOINT ["run.sh"]

下面的run.sh，

#!/bin/sh
while ! bin/kafka_exporter; do
    echo "Waiting for the Kafka cluster to come up..."
    sleep 1
done

下面的docker-compose.yml，

version: '2'

networks:
  app-tier:
    driver: bridge

services:
  zookeeper:
    image: 'bitnami/zookeeper:latest'
    environment:
      - 'ALLOW_ANONYMOUS_LOGIN=yes'
    networks:
      - app-tier
  kafka:
    image: 'bitnami/kafka:latest'
    environment:
      - KAFKA_CFG_ZOOKEEPER_CONNECT=zookeeper:2181
      - ALLOW_PLAINTEXT_LISTENER=yes
    networks:
      - app-tier
  kafka-exporter:
    build: kafka-exporter
    ports:
      - "9308:9308"
    networks:
      - app-tier
    entrypoint: ["run.sh"]
  myapp:
    image: 'bitnami/kafka:latest'
    environment:
      - KAFKA_CFG_ZOOKEEPER_CONNECT=zookeeper:2181
      - ALLOW_PLAINTEXT_LISTENER=yes
    networks:
      - app-tier

在运行docker-compose build && docker-compose up时，我可以从日志中看到，在大约2秒后(在第三次尝试中)，Kafka出口商成功启动：

> docker logs bitnami-docker-kafka-kafka-exporter-1 -f
I0104 16:05:39.765921       8 kafka_exporter.go:769] Starting kafka_exporter (version=1.4.2, branch=non-git, revision=non-git)
F0104 16:05:40.525065       8 kafka_exporter.go:865] Error Init Kafka Client: kafka: client has run out of available brokers to talk to (Is your cluster reachable?)
Waiting for the Kafka cluster to come up...
I0104 16:05:41.538482      16 kafka_exporter.go:769] Starting kafka_exporter (version=1.4.2, branch=non-git, revision=non-git)
F0104 16:05:42.295872      16 kafka_exporter.go:865] Error Init Kafka Client: kafka: client has run out of available brokers to talk to (Is your cluster reachable?)
Waiting for the Kafka cluster to come up...
I0104 16:05:43.307293      24 kafka_exporter.go:769] Starting kafka_exporter (version=1.4.2, branch=non-git, revision=non-git)
I0104 16:05:43.686798      24 kafka_exporter.go:929] Listening on HTTP :9308

Answer 2

对于卡夫卡出口商来说，运行所有所需的依赖关系有点困难。我做了几个简单的步骤如下所示。

第一步

docker pull danielqsj/kafka-exporter:latest

第二步

./bin/zookeeper-server-start.sh config/zookeeper.properties

第三步

./bin/kafka-server-start.sh config/server.properties

第四步

docker run -ti --rm -p 9308:9308 danielqsj/kafka-exporter --kafka.server=host.docker.internal:9092 --log.enable-sarama

如果您注意到上面的命令，我使用了"host.docker.internal“，这将帮助卡夫卡出口商在我的机器上监听本地主机。