写在前面

有很多小公司目前都使用了阿里云aliyun的rds数据库， 但是对于rds的监控基本上都是使用的阿里云的云监控系统， 没有自己的监控插件。 为了解决阿里云锁死小公司监控技术的问题，本人基于流行的Prometheus监控系统，在其 监控插件源代码的起初上进行了修改。这个开源node_exporter 的开源项目是其中之一，旨在解决rds机器层面的数据 采集问题， 调用aliyun的API， 实现一个exporter监控多个rds的功能。 本项目和本人另外一个开源项目mysqld_exporter 都是基于官方prometheus 插件直接修改，基于go语言， 稳定性和性能都可以保障，大家可以放心使用!

Node exporter

Prometheus exporter for hardware and OS metrics exposed by *NIX kernels, written in Go with pluggable metric collectors.

The WMI exporter is recommended for Windows users. To expose NVIDIA GPU metrics, prometheus-dcgm can be used.

Collectors

There is varying support for collectors on each operating system. The tables below list all existing collectors and the supported systems.

Collectors are enabled by providing a --collector.<name> flag. Collectors that are enabled by default can be disabled by providing a --no-collector.<name> flag.

Enabled by default

Name	Description	OS
arp	Exposes ARP statistics from /proc/net/arp.	Linux
bcache	Exposes bcache statistics from /sys/fs/bcache/.	Linux
bonding	Exposes the number of configured and active slaves of Linux bonding interfaces.	Linux
boottime	Exposes system boot time derived from the kern.boottime sysctl.	Darwin, Dragonfly, FreeBSD, NetBSD, OpenBSD, Solaris
conntrack	Shows conntrack statistics (does nothing if no /proc/sys/net/netfilter/ present).	Linux
cpu	Exposes CPU statistics	Darwin, Dragonfly, FreeBSD, Linux, Solaris
cpufreq	Exposes CPU frequency statistics	Linux, Solaris
diskstats	Exposes disk I/O statistics.	Darwin, Linux, OpenBSD
edac	Exposes error detection and correction statistics.	Linux
entropy	Exposes available entropy.	Linux
exec	Exposes execution statistics.	Dragonfly, FreeBSD
filefd	Exposes file descriptor statistics from /proc/sys/fs/file-nr.	Linux
filesystem	Exposes filesystem statistics, such as disk space used.	Darwin, Dragonfly, FreeBSD, Linux, OpenBSD
hwmon	Expose hardware monitoring and sensor data from /sys/class/hwmon/.	Linux
infiniband	Exposes network statistics specific to InfiniBand and Intel OmniPath configurations.	Linux
ipvs	Exposes IPVS status from /proc/net/ip_vs and stats from /proc/net/ip_vs_stats.	Linux
loadavg	Exposes load average.	Darwin, Dragonfly, FreeBSD, Linux, NetBSD, OpenBSD, Solaris
mdadm	Exposes statistics about devices in /proc/mdstat (does nothing if no /proc/mdstat present).	Linux
meminfo	Exposes memory statistics.	Darwin, Dragonfly, FreeBSD, Linux, OpenBSD
netclass	Exposes network interface info from /sys/class/net/	Linux
netdev	Exposes network interface statistics such as bytes transferred.	Darwin, Dragonfly, FreeBSD, Linux, OpenBSD
netstat	Exposes network statistics from /proc/net/netstat. This is the same information as netstat -s.	Linux
nfs	Exposes NFS client statistics from /proc/net/rpc/nfs. This is the same information as nfsstat -c.	Linux
nfsd	Exposes NFS kernel server statistics from /proc/net/rpc/nfsd. This is the same information as nfsstat -s.	Linux
pressure	Exposes pressure stall statistics from /proc/pressure/.	Linux (kernel 4.20+ and/or CONFIG_PSI)
sockstat	Exposes various statistics from /proc/net/sockstat.	Linux
stat	Exposes various statistics from /proc/stat. This includes boot time, forks and interrupts.	Linux
textfile	Exposes statistics read from local disk. The --collector.textfile.directory flag must be set.	any
time	Exposes the current system time.	any
timex	Exposes selected adjtimex(2) system call stats.	Linux
uname	Exposes system information as provided by the uname system call.	FreeBSD, Linux
vmstat	Exposes statistics from /proc/vmstat.	Linux
xfs	Exposes XFS runtime statistics.	Linux (kernel 4.4+)
zfs	Exposes ZFS performance statistics.	Linux, Solaris
cpuRds	Exposes Rds cpu info runtime statistics.	阿里云API
diskRdsStats	Exposes Rds disk info runtime statistics.	阿里云API
meminfoRds	Exposes Rds memory info runtime statistics.	阿里云API
iopsRds	Exposes Rds iops info runtime statistics.	阿里云API

Disabled by default

The perf collector may not work by default on all Linux systems due to kernel configuration and security settings. To allow access, set the following sysctl parameter:

sysctl -w kernel.perf_event_paranoid=X

• 2 allow only user-space measurements (default since Linux 4.6).
• 1 allow both kernel and user measurements (default before Linux 4.6).
• 0 allow access to CPU-specific data but not raw tracepoint samples.
• -1 no restrictions.

Depending on the configured value different metrics will be available, for most cases 0 will provide the most complete set. For more information see man 2 perf_event_open.

Name	Description	OS
buddyinfo	Exposes statistics of memory fragments as reported by /proc/buddyinfo.	Linux
devstat	Exposes device statistics	Dragonfly, FreeBSD
drbd	Exposes Distributed Replicated Block Device statistics (to version 8.4)	Linux
interrupts	Exposes detailed interrupts statistics.	Linux, OpenBSD
ksmd	Exposes kernel and system statistics from /sys/kernel/mm/ksm.	Linux
logind	Exposes session counts from logind.	Linux
meminfo_numa	Exposes memory statistics from /proc/meminfo_numa.	Linux
mountstats	Exposes filesystem statistics from /proc/self/mountstats. Exposes detailed NFS client statistics.	Linux
ntp	Exposes local NTP daemon health to check time	any
processes	Exposes aggregate process statistics from /proc.	Linux
qdisc	Exposes queuing discipline statistics	Linux
runit	Exposes service status from runit.	any
supervisord	Exposes service status from supervisord.	any
systemd	Exposes service and system status from systemd.	Linux
tcpstat	Exposes TCP connection status information from /proc/net/tcp and /proc/net/tcp6. (Warning: the current version has potential performance issues in high load situations.)	Linux
wifi	Exposes WiFi device and station statistics.	Linux
perf	Exposes perf based metrics (Warning: Metrics are dependent on kernel configuration and settings).	Linux

Textfile Collector

The textfile collector is similar to the Pushgateway, in that it allows exporting of statistics from batch jobs. It can also be used to export static metrics, such as what role a machine has. The Pushgateway should be used for service-level metrics. The textfile module is for metrics that are tied to a machine.

To use it, set the --collector.textfile.directory flag on the Node exporter. The collector will parse all files in that directory matching the glob *.prom using the text format. Note: Timestamps are not supported.

To atomically push completion time for a cron job:

echo my_batch_job_completion_time $(date +%s) > /path/to/directory/my_batch_job.prom.$$
mv /path/to/directory/my_batch_job.prom.$$ /path/to/directory/my_batch_job.prom

To statically set roles for a machine using labels:

echo 'role{role="application_server"} 1' > /path/to/directory/role.prom.$$
mv /path/to/directory/role.prom.$$ /path/to/directory/role.prom

Filtering enabled collectors

The node_exporter will expose all metrics from enabled collectors by default. This is the recommended way to collect metrics to avoid errors when comparing metrics of different families.

For advanced use the node_exporter can be passed an optional list of collectors to filter metrics. The collect[] parameter may be used multiple times. In Prometheus configuration you can use this syntax under the scrape config.

  params:
    collect[]:
      - foo
      - bar

This can be useful for having different Prometheus servers collect specific metrics from nodes.

Building and running

Prerequisites:

• Go compiler
• RHEL/CentOS: glibc-static package.

Building:

go get github.com/prometheus/node_exporter
cd ${GOPATH-$HOME/go}/src/github.com/prometheus/node_exporter
make
./node_exporter <flags>

To see all available configuration flags:

./node_exporter -h

Running tests

make test

Using Docker

The node_exporter is designed to monitor the host system. It's not recommended to deploy it as a Docker container because it requires access to the host system. Be aware that any non-root mount points you want to monitor will need to be bind-mounted into the container. If you start container for host monitoring, specify path.rootfs argument. This argument must match path in bind-mount of host root. The node_exporter will use path.rootfs as prefix to access host filesystem.

docker run -d \
  --net="host" \
  --pid="host" \
  -v "/:/host:ro,rslave" \
  quay.io/prometheus/node-exporter \
  --path.rootfs /host

On some systems, the timex collector requires an additional Docker flag, --cap-add=SYS_TIME, in order to access the required syscalls.

Using a third-party repository for RHEL/CentOS/Fedora

There is a community-supplied COPR repository which closely follows upstream releases.

Example config for node_exporter work with prometheus(v2.5)

由于涉及到阿里云的api授权，需要提供accessKeyId和 accessSecret，所以本项目不提供二进制文件，大家将 rds_common 里的配置

const (
	regionId        = "cn-hangzhou"
	accessKeyId     = "accessKeyId"
	accessKeySecret = "accessKeySecret"
)

修改好后，自己进行编译即可。

Prometheus配置：

  - job_name: db-mysql-node 
    scrape_interval: 30s
    params:
        "collect[]": ["cpuRds", "meminfoRds", "diskRdsStats", "iopsRds"]

    consul_sd_configs:
      - server: 'consul-address'
        services: ["db-mysql"]
        tag: "hz-ali"
        tag_separator: "|"

    relabel_configs:

      - source_labels: [__meta_consul_service_id]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: exporter-address:9100

node_exporter配置：

./node_exporter \
--no-collector.arp \
--no-collector.bcache \
--no-collector.bonding \
--no-collector.conntrack \
--collector.cpu \
--collector.cpuRds \
--no-collector.cpufreq \
--collector.diskstats \
--no-collector.edac \
--no-collector.entropy \
--no-collector.filefd \
--no-collector.filesystem \
--no-collector.hwmon \
--no-collector.infiniband \
--no-collector.ipvs \
--no-collector.loadavg \
--no-collector.mdadm \
--collector.meminfo \
--collector.meminfoRds \
--no-collector.netclass \
--no-collector.netdev \
--no-collector.netstat \
--no-collector.nfs \
--no-collector.nfsd \
--no-collector.pressure \
--no-collector.sockstat \
--no-collector.stat \
--no-collector.textfile \
--no-collector.time \
--no-collector.timex \
--no-collector.uname \
--no-collector.vmstat \
--no-collector.xfs \
--no-collector.zfs \
--collector.iopsRds \
--web.max-requests=0 \
--log.level="info"

更多详细内容，参考本人的相关文档： 简书：rds数据库本地化改造
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