kubernetes日志管理最佳实践EFK
一、kubernetes和docker都有哪些日志
- 以上日志都是默认日志，对日志不进行配置就这样
- kubectl logs和docker logs一样的，都是查看容器内部应用的日志
- 对于容器内部应用产生stdout和stderr日志一定会被引擎拦截，如果在应用中通过代码把日志保存到容器内部，那么会产生两份日志；一份原生的日志（代码生成在项目中），一份经过加工过的日志比如json-file保存在/var/lib/docker/containers/<容器>/<容器>.log中。
二、kubernetes日志管理最佳实践EFK(采集)
https://github.com/kubernetes/kubernetes/tree/v1.16.1/cluster/addons/fluentd-elasticsearch
复制代码其实只需要安装fluentd-es到你的k8s集群即可，完全可以将elasticsearch和kibana单独部署，如果有票子可以直接买云厂商现成的，需要的修改fluentd-es的configMap中output：
output.conf: |-
<match **>
@id elasticsearch
@type elasticsearch
...
...
host elasticsearch-logging # 替换集群外部的host
port 9200
user elastic # 如果开启账户验证
password elastic # 如果开启账户验证
...
...
</match>
三、问题排查
1、fluentd-es缓冲区
查看fluentd-es pod日志文件，有个[warn]：
[elasticsearch] failed to write data into buffer by buffer overflow action=:block\n
复制代码我们看采集具体流程
fluentd-es configMap配置文件中的buffer.chunk_limit_size
output.conf: |-
<match **>
@id elasticsearch
@type elasticsearch
@log_level info
type_name _doc
include_tag_key true
host es-cn-36200000.public.elasticsearch.aliyuncs.com
port 9200
user elastic
password elastic
logstash_format true
<buffer>
@type file
path /var/log/fluentd-buffers/kubernetes.system.buffer
flush_mode interval
...
chunk_limit_size 100M # 由原来的2M增加到100M，一般2M就够了，只是为了测试 ：）
...
overflow_action block # 我们看到，这个block就是溢出标志
</buffer>
</match>
如果出现缓冲区出现大量未处理的日志，那么一定是
elasticsearch有性能瓶颈，不能实时获取最新的日志文件，需要优化一下elasticsearch
2、fluentd-es pod重复拉去自身的日志
查看fluentd-es pod日志文件，有好多[warn]：
\\\这种转义字符，大概可以猜到应该是该日志文件经过多次采集，为什么会采集多次呢？我们仔细看该条日志记录的是 我们需要继续修改
fluentd-es configMap，通过exclude_path把这个日志文件排除了 ：
containers.input.conf: |-
<source>
@id fluentd-containers.log
@type tail
path /var/log/containers/*.log
pos_file /var/log/es-containers.log.pos
exclude_path /var/log/containers/fluentd-es*.log # 这里将fluentd-es自己的日志排除，不采集
...
<parse>
..
</parse>
</source>
复制代码3、云厂商elasticsearch
查看fluentd-es pod日志文件，有好多[warn]：
dump an error event: error_class=ArgumentError error=\"log does not exist\"
复制代码一般云厂商提供的elasticsearch套件是不开启允许自动创建索引功能的，需要开启。
4、排查所有问题
将@log_level设置为debug
output.conf: |-
<match **>
@id elasticsearch
@type elasticsearch
@log_level debug # 如果测试没有出现问题，则改回info
...
...
host elasticsearch-logging # 替换集群外部的host
port 9200
user elastic # 如果开启账户验证
password elastic # 如果开启账户验证
...
...
</match>
然后，查看fluentd-es pod日志文件，根据debug提示修复。
四、fluentd-es configMap demo
kind: ConfigMap
apiVersion: v1
metadata:
name: fluentd-es-config-v0.2.0
namespace: kube-system
labels:
addonmanager.kubernetes.io/mode: Reconcile
data:
system.conf: |-
<system>
root_dir /tmp/fluentd-buffers/
</system>
containers.input.conf: |-
# This configuration file for Fluentd / td-agent is used
# to watch changes to Docker log files. The kubelet creates symlinks that
# capture the pod name, namespace, container name & Docker container ID
# to the docker logs for pods in the /var/log/containers directory on the host.
# If running this fluentd configuration in a Docker container, the /var/log
# directory should be mounted in the container.
#
# These logs are then submitted to Elasticsearch which assumes the
# installation of the fluent-plugin-elasticsearch & the
# fluent-plugin-kubernetes_metadata_filter plugins.
# See https://github.com/uken/fluent-plugin-elasticsearch &
# https://github.com/fabric8io/fluent-plugin-kubernetes_metadata_filter for
# more information about the plugins.
#
# Example
# =======
# A line in the Docker log file might look like this JSON:
#
# {"log":"2014/09/25 21:15:03 Got request with path wombat\n",
# "stream":"stderr",
# "time":"2014-09-25T21:15:03.499185026Z"}
#
# The time_format specification below makes sure we properly
# parse the time format produced by Docker. This will be
# submitted to Elasticsearch and should appear like:
# $ curl 'http://elasticsearch-logging:9200/_search?pretty'
# ...
# {
# "_index" : "logstash-2014.09.25",
# "_type" : "fluentd",
# "_id" : "VBrbor2QTuGpsQyTCdfzqA",
# "_score" : 1.0,
# "_source":{"log":"2014/09/25 22:45:50 Got request with path wombat\n",
# "stream":"stderr","tag":"docker.container.all",
# "@timestamp":"2014-09-25T22:45:50+00:00"}
# },
# ...
#
# The Kubernetes fluentd plugin is used to write the Kubernetes metadata to the log
# record & add labels to the log record if properly configured. This enables users
# to filter & search logs on any metadata.
# For example a Docker container's logs might be in the directory:
#
# /var/lib/docker/containers/997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b
#
# and in the file:
#
# 997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b-json.log
#
# where 997599971ee6... is the Docker ID of the running container.
# The Kubernetes kubelet makes a symbolic link to this file on the host machine
# in the /var/log/containers directory which includes the pod name and the Kubernetes
# container name:
#
# synthetic-logger-0.25lps-pod_default_synth-lgr-997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b.log
# ->
# /var/lib/docker/containers/997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b/997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b-json.log
#
# The /var/log directory on the host is mapped to the /var/log directory in the container
# running this instance of Fluentd and we end up collecting the file:
#
# /var/log/containers/synthetic-logger-0.25lps-pod_default_synth-lgr-997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b.log
#
# This results in the tag:
#
# var.log.containers.synthetic-logger-0.25lps-pod_default_synth-lgr-997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b.log
#
# The Kubernetes fluentd plugin is used to extract the namespace, pod name & container name
# which are added to the log message as a kubernetes field object & the Docker container ID
# is also added under the docker field object.
# The final tag is:
#
# kubernetes.var.log.containers.synthetic-logger-0.25lps-pod_default_synth-lgr-997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b.log
#
# And the final log record look like:
#
# {
# "log":"2014/09/25 21:15:03 Got request with path wombat\n",
# "stream":"stderr",
# "time":"2014-09-25T21:15:03.499185026Z",
# "kubernetes": {
# "namespace": "default",
# "pod_name": "synthetic-logger-0.25lps-pod",
# "container_name": "synth-lgr"
# },
# "docker": {
# "container_id": "997599971ee6366d4a5920d25b79286ad45ff37a74494f262e3bc98d909d0a7b"
# }
# }
#
# This makes it easier for users to search for logs by pod name or by
# the name of the Kubernetes container regardless of how many times the
# Kubernetes pod has been restarted (resulting in a several Docker container IDs).
# Json Log Example:
# {"log":"[info:2016-02-16T16:04:05.930-08:00] Some log text here\n","stream":"stdout","time":"2016-02-17T00:04:05.931087621Z"}
# CRI Log Example:
# 2016-02-17T00:04:05.931087621Z stdout F [info:2016-02-16T16:04:05.930-08:00] Some log text here
<source>
@id fluentd-containers.log
@type tail
path /var/log/containers/*.log
pos_file /var/log/es-containers.log.pos
exclude_path /var/log/containers/fluentd-es*.log
tag raw.kubernetes.*
read_from_head true
<parse>
@type multi_format
<pattern>
format json
time_key time
time_format %Y-%m-%dT%H:%M:%S.%NZ
</pattern>
<pattern>
format /^(?<time>.+) (?<stream>stdout|stderr) [^ ]* (?<log>.*)$/
time_format %Y-%m-%dT%H:%M:%S.%N%:z
</pattern>
</parse>
</source>
# Detect exceptions in the log output and forward them as one log entry.
<match raw.kubernetes.**>
@id raw.kubernetes
@type detect_exceptions
remove_tag_prefix raw
message log
stream stream
multiline_flush_interval 5
max_bytes 500000
max_lines 1000
</match>
# Concatenate multi-line logs
<filter **>
@id filter_concat
@type concat
key message
multiline_end_regexp /\n$/
separator ""
</filter>
# Enriches records with Kubernetes metadata
<filter kubernetes.**>
@id filter_kubernetes_metadata
@type kubernetes_metadata
</filter>
# Fixes json fields in Elasticsearch
<filter kubernetes.**>
@id filter_parser
@type parser
key_name log
reserve_data true
remove_key_name_field true
<parse>
@type multi_format
<pattern>
format json
</pattern>
<pattern>
format none
</pattern>
</parse>
</filter>
system.input.conf: |-
# Example:
# 2015-12-21 23:17:22,066 [salt.state ][INFO ] Completed state [net.ipv4.ip_forward] at time 23:17:22.066081
<source>
@id minion
@type tail
format /^(?<time>[^ ]* [^ ,]*)[^\[]*\[[^\]]*\]\[(?<severity>[^ \]]*) *\] (?<message>.*)$/
time_format %Y-%m-%d %H:%M:%S
path /var/log/salt/minion
pos_file /var/log/salt.pos
tag salt
</source>
# Example:
# Dec 21 23:17:22 gke-foo-1-1-4b5cbd14-node-4eoj startupscript: Finished running startup script /var/run/google.startup.script
# <source>
# @id startupscript.log
# @type tail
# format syslog
# path /var/log/startupscript.log
# pos_file /var/log/es-startupscript.log.pos
# tag startupscript
# </source>
# Examples:
# time="2016-02-04T06:51:03.053580605Z" level=info msg="GET /containers/json"
# time="2016-02-04T07:53:57.505612354Z" level=error msg="HTTP Error" err="No such image: -f" statusCode=404
# TODO(random-liu): Remove this after cri container runtime rolls out.
# <source>
# @id docker.log
# @type tail
# format /^time="(?<time>[^)]*)" level=(?<severity>[^ ]*) msg="(?<message>[^"]*)"( err="(?<error>[^"]*)")?( statusCode=($<status_code>\d+))?/
# path /var/log/docker.log
# pos_file /var/log/es-docker.log.pos
# tag docker
# </source>
# Example:
# 2016/02/04 06:52:38 filePurge: successfully removed file /var/etcd/data/member/wal/00000000000006d0-00000000010a23d1.wal
# <source>
# @id etcd.log
# @type tail
# # Not parsing this, because it doesn't have anything particularly useful to
# # parse out of it (like severities).
# format none
# path /var/log/etcd.log
# pos_file /var/log/es-etcd.log.pos
# tag etcd
# </source>
# Multi-line parsing is required for all the kube logs because very large log
# statements, such as those that include entire object bodies, get split into
# multiple lines by glog.
# Example:
# I0204 07:32:30.020537 3368 server.go:1048] POST /stats/container/: (13.972191ms) 200 [[Go-http-client/1.1] 10.244.1.3:40537]
# <source>
# @id kubelet.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/kubelet.log
# pos_file /var/log/es-kubelet.log.pos
# tag kubelet
# </source>
# Example:
# I1118 21:26:53.975789 6 proxier.go:1096] Port "nodePort for kube-system/default-http-backend:http" (:31429/tcp) was open before and is still needed
# <source>
# @id kube-proxy.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/kube-proxy.log
# pos_file /var/log/es-kube-proxy.log.pos
# tag kube-proxy
# </source>
# Example:
# I0204 07:00:19.604280 5 handlers.go:131] GET /api/v1/nodes: (1.624207ms) 200 [[kube-controller-manager/v1.1.3 (linux/amd64) kubernetes/6a81b50] 127.0.0.1:38266]
# <source>
# @id kube-apiserver.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/kube-apiserver.log
# pos_file /var/log/es-kube-apiserver.log.pos
# tag kube-apiserver
# </source>
# Example:
# I0204 06:55:31.872680 5 servicecontroller.go:277] LB already exists and doesn't need update for service kube-system/kube-ui
# <source>
# @id kube-controller-manager.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/kube-controller-manager.log
# pos_file /var/log/es-kube-controller-manager.log.pos
# tag kube-controller-manager
# </source>
# Example:
# W0204 06:49:18.239674 7 reflector.go:245] pkg/scheduler/factory/factory.go:193: watch of *api.Service ended with: 401: The event in requested index is outdated and cleared (the requested history has been cleared [2578313/2577886]) [2579312]
# <source>
# @id kube-scheduler.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/kube-scheduler.log
# pos_file /var/log/es-kube-scheduler.log.pos
# tag kube-scheduler
# </source>
# Example:
# I0603 15:31:05.793605 6 cluster_manager.go:230] Reading config from path /etc/gce.conf
# <source>
# @id glbc.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/glbc.log
# pos_file /var/log/es-glbc.log.pos
# tag glbc
# </source>
# Example:
# I0603 15:31:05.793605 6 cluster_manager.go:230] Reading config from path /etc/gce.conf
# <source>
# @id cluster-autoscaler.log
# @type tail
# format multiline
# multiline_flush_interval 5s
# format_firstline /^\w\d{4}/
# format1 /^(?<severity>\w)(?<time>\d{4} [^\s]*)\s+(?<pid>\d+)\s+(?<source>[^ \]]+)\] (?<message>.*)/
# time_format %m%d %H:%M:%S.%N
# path /var/log/cluster-autoscaler.log
# pos_file /var/log/es-cluster-autoscaler.log.pos
# tag cluster-autoscaler
# </source>
# Logs from systemd-journal for interesting services.
# TODO(random-liu): Remove this after cri container runtime rolls out.
<source>
@id journald-docker
@type systemd
matches [{ "_SYSTEMD_UNIT": "docker.service" }]
<storage>
@type local
persistent true
path /var/log/journald-docker.pos
</storage>
read_from_head true
tag docker
</source>
<source>
@id journald-container-runtime
@type systemd
matches [{ "_SYSTEMD_UNIT": "{{ fluentd_container_runtime_service }}.service" }]
<storage>
@type local
persistent true
path /var/log/journald-container-runtime.pos
</storage>
read_from_head true
tag container-runtime
</source>
<source>
@id journald-kubelet
@type systemd
matches [{ "_SYSTEMD_UNIT": "kubelet.service" }]
<storage>
@type local
persistent true
path /var/log/journald-kubelet.pos
</storage>
read_from_head true
tag kubelet
</source>
<source>
@id journald-node-problem-detector
@type systemd
matches [{ "_SYSTEMD_UNIT": "node-problem-detector.service" }]
<storage>
@type local
persistent true
path /var/log/journald-node-problem-detector.pos
</storage>
read_from_head true
tag node-problem-detector
</source>
<source>
@id kernel
@type systemd
matches [{ "_TRANSPORT": "kernel" }]
<storage>
@type local
persistent true
path /var/log/kernel.pos
</storage>
<entry>
fields_strip_underscores true
fields_lowercase true
</entry>
read_from_head true
tag kernel
</source>
forward.input.conf: |-
# Takes the messages sent over TCP
<source>
@id forward
@type forward
</source>
monitoring.conf: |-
# Prometheus Exporter Plugin
# input plugin that exports metrics
<source>
@id prometheus
@type prometheus
</source>
<source>
@id monitor_agent
@type monitor_agent
</source>
# input plugin that collects metrics from MonitorAgent
<source>
@id prometheus_monitor
@type prometheus_monitor
<labels>
host ${hostname}
</labels>
</source>
# input plugin that collects metrics for output plugin
<source>
@id prometheus_output_monitor
@type prometheus_output_monitor
<labels>
host ${hostname}
</labels>
</source>
# input plugin that collects metrics for in_tail plugin
<source>
@id prometheus_tail_monitor
@type prometheus_tail_monitor
<labels>
host ${hostname}
</labels>
</source>
output.conf: |-
<match **>
@id elasticsearch
@type elasticsearch
@log_level debug
type_name doc
include_tag_key true
host es-cn-11111.public.elasticsearch.aliyuncs.com
port 9200
user elastic
password 111111
logstash_format true
<buffer>
@type file
path /var/log/fluentd-buffers/kubernetes.system.buffer
flush_mode interval
retry_type exponential_backoff
flush_thread_count 2
flush_interval 5s
retry_forever
retry_max_interval 30
chunk_limit_size 100M
queue_limit_length 8
overflow_action block
</buffer>
</match>
DeamonSet
https://raw.githubusercontent.com/kubernetes/kubernetes/v1.16.1/cluster/addons/fluentd-elasticsearch/fluentd-es-ds.yaml
