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張 旭

Logstash Alternatives: Pros & Cons of 5 Log Shippers [2019] - Sematext - 0 views

  • In this case, Elasticsearch. And because Elasticsearch can be down or struggling, or the network can be down, the shipper would ideally be able to buffer and retry
  • Logstash is typically used for collecting, parsing, and storing logs for future use as part of log management.
  • Logstash’s biggest con or “Achille’s heel” has always been performance and resource consumption (the default heap size is 1GB).
  • ...37 more annotations...
  • This can be a problem for high traffic deployments, when Logstash servers would need to be comparable with the Elasticsearch ones.
  • Filebeat was made to be that lightweight log shipper that pushes to Logstash or Elasticsearch.
  • differences between Logstash and Filebeat are that Logstash has more functionality, while Filebeat takes less resources.
  • Filebeat is just a tiny binary with no dependencies.
  • For example, how aggressive it should be in searching for new files to tail and when to close file handles when a file didn’t get changes for a while.
  • For example, the apache module will point Filebeat to default access.log and error.log paths
  • Filebeat’s scope is very limited,
  • Initially it could only send logs to Logstash and Elasticsearch, but now it can send to Kafka and Redis, and in 5.x it also gains filtering capabilities.
  • Filebeat can parse JSON
  • you can push directly from Filebeat to Elasticsearch, and have Elasticsearch do both parsing and storing.
  • You shouldn’t need a buffer when tailing files because, just as Logstash, Filebeat remembers where it left off
  • For larger deployments, you’d typically use Kafka as a queue instead, because Filebeat can talk to Kafka as well
  • The default syslog daemon on most Linux distros, rsyslog can do so much more than just picking logs from the syslog socket and writing to /var/log/messages.
  • It can tail files, parse them, buffer (on disk and in memory) and ship to a number of destinations, including Elasticsearch.
  • rsyslog is the fastest shipper
  • Its grammar-based parsing module (mmnormalize) works at constant speed no matter the number of rules (we tested this claim).
  • use it as a simple router/shipper, any decent machine will be limited by network bandwidth
  • It’s also one of the lightest parsers you can find, depending on the configured memory buffers.
  • rsyslog requires more work to get the configuration right
  • the main difference between Logstash and rsyslog is that Logstash is easier to use while rsyslog lighter.
  • rsyslog fits well in scenarios where you either need something very light yet capable (an appliance, a small VM, collecting syslog from within a Docker container).
  • rsyslog also works well when you need that ultimate performance.
  • syslog-ng as an alternative to rsyslog (though historically it was actually the other way around).
  • a modular syslog daemon, that can do much more than just syslog
  • Unlike rsyslog, it features a clear, consistent configuration format and has nice documentation.
  • Similarly to rsyslog, you’d probably want to deploy syslog-ng on boxes where resources are tight, yet you do want to perform potentially complex processing.
  • syslog-ng has an easier, more polished feel than rsyslog, but likely not that ultimate performance
  • Fluentd was built on the idea of logging in JSON wherever possible (which is a practice we totally agree with) so that log shippers down the line don’t have to guess which substring is which field of which type.
  • Fluentd plugins are in Ruby and very easy to write.
  • structured data through Fluentd, it’s not made to have the flexibility of other shippers on this list (Filebeat excluded).
  • Fluent Bit, which is to Fluentd similar to how Filebeat is for Logstash.
  • Fluentd is a good fit when you have diverse or exotic sources and destinations for your logs, because of the number of plugins.
  • Splunk isn’t a log shipper, it’s a commercial logging solution
  • Graylog is another complete logging solution, an open-source alternative to Splunk.
  • everything goes through graylog-server, from authentication to queries.
  • Graylog is nice because you have a complete logging solution, but it’s going to be harder to customize than an ELK stack.
  • it depends
張 旭

Load balancing with ProxySQL - 0 views

  • accepts incoming traffic from MySQL clients and forwards it to backend MySQL servers.
張 旭

手动安装 Prometheus · 从 Docker 到 Kubernetes 进阶手册 - 1 views

  • 参数storage.tsdb.path指定了 TSDB 数据的存储路径、通过storage.tsdb.retention设置了保留多长时间的数据,还有下面的web.enable-admin-api参数可以用来开启对 admin api 的访问权限,参数web.enable-lifecycle非常重要,用来开启支持热更新的,有了这个参数之后,prometheus.yml 配置文件只要更新了,通过执行localhost:9090/-/reload就会立即生效,所以一定要加上这个参数。
  • Prometheus 由多个组件组成,但是其中许多组件是可选的: Prometheus Server:用于抓取指标、存储时间序列数据 exporter:暴露指标让任务来抓 pushgateway:push 的方式将指标数据推送到该网关 alertmanager:处理报警的报警组件 adhoc:用于数据查询
  • scrape_configs 用于控制 prometheus 监控哪些资源。
  • ...6 more annotations...
  • prometheus 通过 HTTP 的方式来暴露的它本身的监控数据
  • prometheus 默认会通过目标的/metrics路径采集 metrics
  • 需要配置 rbac 认证,因为我们需要在 prometheus 中去访问 Kubernetes 的相关信息
  • 要获取的资源信息,在每一个 namespace 下面都有可能存在,所以我们这里使用的是 ClusterRole 的资源对象,值得一提的是我们这里的权限规则声明中有一个nonResourceURLs的属性,是用来对非资源型 metrics 进行操作的权限声明
  • 添加一个securityContext的属性,将其中的runAsUser设置为0,这是因为现在的 prometheus 运行过程中使用的用户是 nobody,否则会出现下面的permission denied之类的权限错误
  • PromQL其实就是 prometheus 便于数据聚合展示开发的一套 ad hoc 查询语言的,你想要查什么找对应函数取你的数据好了。
  •  
    "参数storage.tsdb.path指定了 TSDB 数据的存储路径、通过storage.tsdb.retention设置了保留多长时间的数据,还有下面的web.enable-admin-api参数可以用来开启对 admin api 的访问权限,参数web.enable-lifecycle非常重要,用来开启支持热更新的,有了这个参数之后,prometheus.yml 配置文件只要更新了,通过执行localhost:9090/-/reload就会立即生效,所以一定要加上这个参数。"
張 旭

Kubernetes 基本概念 · Kubernetes指南 - 0 views

  • Container(容器)是一种便携式、轻量级的操作系统级虚拟化技术。它使用 namespace 隔离不同的软件运行环境,并通过镜像自包含软件的运行环境,从而使得容器可以很方便的在任何地方运行。
  • 每个应用程序用容器封装,管理容器部署就等同于管理应用程序部署。+
  • Pod 是一组紧密关联的容器集合,它们共享 PID、IPC、Network 和 UTS namespace,是 Kubernetes 调度的基本单位。
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  • 进程间通信和文件共享
  • 在 Kubernetes 中,所有对象都使用 manifest(yaml 或 json)来定义
  • Node 是 Pod 真正运行的主机,可以是物理机,也可以是虚拟机。
  • 每个 Node 节点上至少要运行 container runtime(比如 docker 或者 rkt)、kubelet 和 kube-proxy 服务。
  • 常见的 pods, services, replication controllers 和 deployments 等都是属于某一个 namespace 的(默认是 default)
  • node, persistentVolumes 等则不属于任何 namespace
  • Service 是应用服务的抽象,通过 labels 为应用提供负载均衡和服务发现。
  • 匹配 labels 的 Pod IP 和端口列表组成 endpoints,由 kube-proxy 负责将服务 IP 负载均衡到这些 endpoints 上。
  • 每个 Service 都会自动分配一个 cluster IP(仅在集群内部可访问的虚拟地址)和 DNS 名
  •  
    "常见的 pods, services, replication controllers 和 deployments 等都是属于某一个 namespace 的(默认是 default),而 node, persistentVolumes 等则不属于任何 namespace。"
張 旭

Running rootless Podman as a non-root user | Enable Sysadmin - 0 views

  • By default, rootless Podman runs as root within the container.
  • the processes in the container have the default list of namespaced capabilities which allow the processes to act like root inside of the user namespace
  • the directory is owned by UID 26, but UID 26 is not mapped into the container and is not the same UID that Postgres runs with while in the container.
  • ...8 more annotations...
  • Podman launches a container inside of the user namespace, which is mapped with the range of UIDs defined for the user in /etc/subuid and /etc/subgid
  • The easy solution to this problem is to chown the html directory to match the UID that Postgresql runs with inside of the container.
  • use the podman unshare command, which drops you into the same user namespace that rootless Podman uses
  • This setup also means that the processes inside of the container are running as the user’s UID. If the container process escaped the container, the process would have full access to files in your home directory based on UID separation.
  • SELinux would still block the access, but I have heard that some people disable SELinux.
  • If you run the processes within the container as a different non-root UID, however, then those processes will run as that UID. If they escape the container, they would only have world access to content in your home directory.
  • run a podman unshare command, or set up the directories' group ownership as owned by your UID (root inside of the container).
  • running containers as non-root should always be your top priority for security reasons.
crazylion lee

Apache Helix - Near-Realtime Rsync Replicated File System - 1 views

  •  
    "Near-Realtime Rsync Replicated File System "
crazylion lee

Little Snitch - 1 views

  •  
    "As soon as you're connected to the Internet, applications can potentially send whatever they want to wherever they want. Most often they do this to your benefit. But sometimes, like in case of tracking software, trojans or other malware, they don't. But you don't notice anything, because all of this happens invisibly under the hood."
張 旭

Tagging AWS resources - AWS General Reference - 0 views

  • assign metadata to your AWS resources in the form of tags.
  • a user-defined key and value
  • Tag keys are case sensitive.
  • ...17 more annotations...
  • tag values are case sensitive.
  • Tags are accessible to many AWS services, including billing.
  • personally identifiable information (PII)
  • apply it consistently across all resource types.
  • Use automated tools to help manage resource tags.
  • Use too many tags rather than too few tags.
  • Tag policies let you specify tagging rules that define valid key names and the values that are valid for each key.
  • Name – Identify individual resources
  • Environment – Distinguish between development, test, and production resources
  • Project – Identify projects that the resource supports
  • Owner – Identify who is responsible for the resource
  • Each resource can have a maximum of 50 user created tags.
  • For each resource, each tag key must be unique, and each tag key can have only one value.
  • Tag keys and values are case sensitive.
  • decide on a strategy for capitalizing tags, and consistently implement that strategy across all resource types.
  • AWS Cost Explorer and detailed billing reports let you break down AWS costs by tag.
  • An effective tagging strategy uses standardized tags and applies them consistently and programmatically across AWS resources.
  •  
    "assign metadata to your AWS resources in the form of tags."
張 旭

Ingress - Kubernetes - 0 views

  • An API object that manages external access to the services in a cluster, typically HTTP.
  • load balancing
  • SSL termination
  • ...62 more annotations...
  • name-based virtual hosting
  • Edge routerA router that enforces the firewall policy for your cluster.
  • Cluster networkA set of links, logical or physical, that facilitate communication within a cluster according to the Kubernetes networking model.
  • A Kubernetes ServiceA way to expose an application running on a set of Pods as a network service. that identifies a set of Pods using labelTags objects with identifying attributes that are meaningful and relevant to users. selectors.
  • Services are assumed to have virtual IPs only routable within the cluster network.
  • Ingress exposes HTTP and HTTPS routes from outside the cluster to services within the cluster.
  • Traffic routing is controlled by rules defined on the Ingress resource.
  • An Ingress can be configured to give Services externally-reachable URLs, load balance traffic, terminate SSL / TLS, and offer name based virtual hosting.
  • Exposing services other than HTTP and HTTPS to the internet typically uses a service of type Service.Type=NodePort or Service.Type=LoadBalancer.
  • You must have an ingress controller to satisfy an Ingress. Only creating an Ingress resource has no effect.
  • As with all other Kubernetes resources, an Ingress needs apiVersion, kind, and metadata fields
  • Ingress frequently uses annotations to configure some options depending on the Ingress controller,
  • Ingress resource only supports rules for directing HTTP traffic.
  • An optional host.
  • A list of paths
  • A backend is a combination of Service and port names
  • has an associated backend
  • Both the host and path must match the content of an incoming request before the load balancer directs traffic to the referenced Service.
  • HTTP (and HTTPS) requests to the Ingress that matches the host and path of the rule are sent to the listed backend.
  • A default backend is often configured in an Ingress controller to service any requests that do not match a path in the spec.
  • An Ingress with no rules sends all traffic to a single default backend.
  • Ingress controllers and load balancers may take a minute or two to allocate an IP address.
  • A fanout configuration routes traffic from a single IP address to more than one Service, based on the HTTP URI being requested.
  • nginx.ingress.kubernetes.io/rewrite-target: /
  • describe ingress
  • get ingress
  • Name-based virtual hosts support routing HTTP traffic to multiple host names at the same IP address.
  • route requests based on the Host header.
  • an Ingress resource without any hosts defined in the rules, then any web traffic to the IP address of your Ingress controller can be matched without a name based virtual host being required.
  • secure an Ingress by specifying a SecretStores sensitive information, such as passwords, OAuth tokens, and ssh keys. that contains a TLS private key and certificate.
  • Currently the Ingress only supports a single TLS port, 443, and assumes TLS termination.
  • An Ingress controller is bootstrapped with some load balancing policy settings that it applies to all Ingress, such as the load balancing algorithm, backend weight scheme, and others.
  • persistent sessions, dynamic weights) are not yet exposed through the Ingress. You can instead get these features through the load balancer used for a Service.
  • review the controller specific documentation to see how they handle health checks
  • edit ingress
  • After you save your changes, kubectl updates the resource in the API server, which tells the Ingress controller to reconfigure the load balancer.
  • kubectl replace -f on a modified Ingress YAML file.
  • Node: A worker machine in Kubernetes, part of a cluster.
  • in most common Kubernetes deployments, nodes in the cluster are not part of the public internet.
  • Edge router: A router that enforces the firewall policy for your cluster.
  • a gateway managed by a cloud provider or a physical piece of hardware.
  • Cluster network: A set of links, logical or physical, that facilitate communication within a cluster according to the Kubernetes networking model.
  • Service: A Kubernetes Service that identifies a set of Pods using label selectors.
  • An Ingress may be configured to give Services externally-reachable URLs, load balance traffic, terminate SSL / TLS, and offer name-based virtual hosting.
  • An Ingress does not expose arbitrary ports or protocols.
  • You must have an Ingress controller to satisfy an Ingress. Only creating an Ingress resource has no effect.
  • The name of an Ingress object must be a valid DNS subdomain name
  • The Ingress spec has all the information needed to configure a load balancer or proxy server.
  • Ingress resource only supports rules for directing HTTP(S) traffic.
  • An Ingress with no rules sends all traffic to a single default backend and .spec.defaultBackend is the backend that should handle requests in that case.
  • If defaultBackend is not set, the handling of requests that do not match any of the rules will be up to the ingress controller
  • A common usage for a Resource backend is to ingress data to an object storage backend with static assets.
  • Exact: Matches the URL path exactly and with case sensitivity.
  • Prefix: Matches based on a URL path prefix split by /. Matching is case sensitive and done on a path element by element basis.
  • multiple paths within an Ingress will match a request. In those cases precedence will be given first to the longest matching path.
  • Hosts can be precise matches (for example “foo.bar.com”) or a wildcard (for example “*.foo.com”).
  • No match, wildcard only covers a single DNS label
  • Each Ingress should specify a class, a reference to an IngressClass resource that contains additional configuration including the name of the controller that should implement the class.
  • secure an Ingress by specifying a Secret that contains a TLS private key and certificate.
  • The Ingress resource only supports a single TLS port, 443, and assumes TLS termination at the ingress point (traffic to the Service and its Pods is in plaintext).
  • TLS will not work on the default rule because the certificates would have to be issued for all the possible sub-domains.
  • hosts in the tls section need to explicitly match the host in the rules section.
張 旭

CDC and DDL Changes to Source Tables - Microsoft® SQL Server 2012 Unleashed [... - 1 views

  • One of the common challenges when capturing data changes from your source tables is how to handle DDL changes to the source tables.
  • Change Data Capture
張 旭

Auto DevOps | GitLab - 0 views

  • Scan for vulnerabilities and security flaws.
  • Auto DevOps starts by building and testing your application.
  • preview your changes in a per-branch basis.
  • ...9 more annotations...
  • you don’t need to set up the deployment upfront. Auto DevOps still builds and tests your application. You can define the deployment later.
  • ship your app first, then explore the customizations later.
  • Consistency
  • Auto DevOps works with any Kubernetes cluster.
  • To use Auto DevOps for individual projects, you can enable it in a project-by-project basis.
  • Only project Maintainers can enable or disable Auto DevOps at the project level.
  • We strongly advise you to use GitLab Container Registry with Auto DevOps to simplify configuration and prevent any unforeseen issues.
  • The GitLab integration with Helm does not support installing applications when behind a proxy.
    • 張 旭
       
      已經廢棄了,不要用
    • 張 旭
       
      已經廢棄了,不要用
張 旭

The dangers of UFW + Docker | Viktor's ramblings - 0 views

  • UFW doesn’t tell you iptables true state (not shocking, but still).
  •  
    "UFW doesn't tell you iptables true state (not shocking, but still). "
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