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張 旭

Cluster Networking - Kubernetes - 0 views

kubernetes.io/...networking

kubernetes networking network system

shared by 張 旭 on 08 Jul 19 - No Cached
  • Networking is a central part of Kubernetes, but it can be challenging to understand exactly how it is expected to work
  • Highly-coupled container-to-container communications
  • Pod-to-Pod communications
  • ...57 more annotations...
  • this is the primary focus of this document
    • 張 旭
      張 旭 on 27 Aug 21
       
      Cluster Networking 所關注處理的是： Pod 到 Pod 之間的連線
  • Pod-to-Service communications
  • External-to-Service communications
  • Kubernetes is all about sharing machines between applications.
  • sharing machines requires ensuring that two applications do not try to use the same ports.
  • Dynamic port allocation brings a lot of complications to the system
  • Every Pod gets its own IP address
  • do not need to explicitly create links between Pods
  • almost never need to deal with mapping container ports to host ports.
  • Pods can be treated much like VMs or physical hosts from the perspectives of port allocation, naming, service discovery, load balancing, application configuration, and migration.
  • pods on a node can communicate with all pods on all nodes without NAT
  • agents on a node (e.g. system daemons, kubelet) can communicate with all pods on that node
  • pods in the host network of a node can communicate with all pods on all nodes without NAT
  • If your job previously ran in a VM, your VM had an IP and could talk to other VMs in your project. This is the same basic model.
  • containers within a Pod share their network namespaces - including their IP address
  • containers within a Pod can all reach each other’s ports on localhost
  • containers within a Pod must coordinate port usage
  • “IP-per-pod” model.
  • request ports on the Node itself which forward to your Pod (called host ports), but this is a very niche operation
  • The Pod itself is blind to the existence or non-existence of host ports.
  • AOS is an Intent-Based Networking system that creates and manages complex datacenter environments from a simple integrated platform.
  • Cisco Application Centric Infrastructure offers an integrated overlay and underlay SDN solution that supports containers, virtual machines, and bare metal servers.
  • AOS Reference Design currently supports Layer-3 connected hosts that eliminate legacy Layer-2 switching problems.
  • The AWS VPC CNI offers integrated AWS Virtual Private Cloud (VPC) networking for Kubernetes clusters.
  • users can apply existing AWS VPC networking and security best practices for building Kubernetes clusters.
  • Using this CNI plugin allows Kubernetes pods to have the same IP address inside the pod as they do on the VPC network.
  • The CNI allocates AWS Elastic Networking Interfaces (ENIs) to each Kubernetes node and using the secondary IP range from each ENI for pods on the node.
  • Big Cloud Fabric is a cloud native networking architecture, designed to run Kubernetes in private cloud/on-premises environments.
  • Cilium is L7/HTTP aware and can enforce network policies on L3-L7 using an identity based security model that is decoupled from network addressing.
  • CNI-Genie is a CNI plugin that enables Kubernetes to simultaneously have access to different implementations of the Kubernetes network model in runtime.
  • CNI-Genie also supports assigning multiple IP addresses to a pod, each from a different CNI plugin.
  • cni-ipvlan-vpc-k8s contains a set of CNI and IPAM plugins to provide a simple, host-local, low latency, high throughput, and compliant networking stack for Kubernetes within Amazon Virtual Private Cloud (VPC) environments by making use of Amazon Elastic Network Interfaces (ENI) and binding AWS-managed IPs into Pods using the Linux kernel’s IPvlan driver in L2 mode.
  • to be straightforward to configure and deploy within a VPC
  • Contiv provides configurable networking
  • Contrail, based on Tungsten Fabric, is a truly open, multi-cloud network virtualization and policy management platform.
  • DANM is a networking solution for telco workloads running in a Kubernetes cluster.
  • Flannel is a very simple overlay network that satisfies the Kubernetes requirements.
  • Any traffic bound for that subnet will be routed directly to the VM by the GCE network fabric.
  • sysctl net.ipv4.ip_forward=1
  • Jaguar provides overlay network using vxlan and Jaguar CNIPlugin provides one IP address per pod.
  • Knitter is a network solution which supports multiple networking in Kubernetes.
  • Kube-OVN is an OVN-based kubernetes network fabric for enterprises.
  • Kube-router provides a Linux LVS/IPVS-based service proxy, a Linux kernel forwarding-based pod-to-pod networking solution with no overlays, and iptables/ipset-based network policy enforcer.
  • If you have a “dumb” L2 network, such as a simple switch in a “bare-metal” environment, you should be able to do something similar to the above GCE setup.
  • Multus is a Multi CNI plugin to support the Multi Networking feature in Kubernetes using CRD based network objects in Kubernetes.
  • NSX-T can provide network virtualization for a multi-cloud and multi-hypervisor environment and is focused on emerging application frameworks and architectures that have heterogeneous endpoints and technology stacks.
  • NSX-T Container Plug-in (NCP) provides integration between NSX-T and container orchestrators such as Kubernetes
  • Nuage uses the open source Open vSwitch for the data plane along with a feature rich SDN Controller built on open standards.
  • OpenVSwitch is a somewhat more mature but also complicated way to build an overlay network
  • OVN is an opensource network virtualization solution developed by the Open vSwitch community.
  • Project Calico is an open source container networking provider and network policy engine.
  • Calico provides a highly scalable networking and network policy solution for connecting Kubernetes pods based on the same IP networking principles as the internet
  • Calico can be deployed without encapsulation or overlays to provide high-performance, high-scale data center networking.
  • Calico can also be run in policy enforcement mode in conjunction with other networking solutions such as Flannel, aka canal, or native GCE, AWS or Azure networking.
  • Romana is an open source network and security automation solution that lets you deploy Kubernetes without an overlay network
  • Weave Net runs as a CNI plug-in or stand-alone. In either version, it doesn’t require any configuration or extra code to run, and in both cases, the network provides one IP address per pod - as is standard for Kubernetes.
  • The network model is implemented by the container runtime on each node.
張 旭

Ingress - Kubernetes - 0 views

kubernetes.io/...ingress

kubernetes networking network ingress

shared by 張 旭 on 04 Jul 19 - No Cached
  • 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

Creating a cluster with kubeadm | Kubernetes - 0 views

kubernetes.io/...create-cluster-kubeadm

kubernetes networking

shared by 張 旭 on 25 Jan 23 - No Cached
  • (Recommended) If you have plans to upgrade this single control-plane kubeadm cluster to high availability you should specify the --control-plane-endpoint to set the shared endpoint for all control-plane nodes
  • set the --pod-network-cidr to a provider-specific value.
  • kubeadm tries to detect the container runtime by using a list of well known endpoints.
  • ...12 more annotations...
  • kubeadm uses the network interface associated with the default gateway to set the advertise address for this particular control-plane node's API server. To use a different network interface, specify the --apiserver-advertise-address=<ip-address> argument to kubeadm init
  • Do not share the admin.conf file with anyone and instead grant users custom permissions by generating them a kubeconfig file using the kubeadm kubeconfig user command.
  • The token is used for mutual authentication between the control-plane node and the joining nodes. The token included here is secret. Keep it safe, because anyone with this token can add authenticated nodes to your cluster.
  • You must deploy a Container Network Interface (CNI) based Pod network add-on so that your Pods can communicate with each other. Cluster DNS (CoreDNS) will not start up before a network is installed.
  • Take care that your Pod network must not overlap with any of the host networks
  • Make sure that your Pod network plugin supports RBAC, and so do any manifests that you use to deploy it.
  • You can install only one Pod network per cluster.
  • The cluster created here has a single control-plane node, with a single etcd database running on it.
  • The node-role.kubernetes.io/control-plane label is such a restricted label and kubeadm manually applies it using a privileged client after a node has been created.
  • By default, your cluster will not schedule Pods on the control plane nodes for security reasons.
  • kubectl taint nodes --all node-role.kubernetes.io/control-plane-
  • remove the node-role.kubernetes.io/control-plane:NoSchedule taint from any nodes that have it, including the control plane nodes, meaning that the scheduler will then be able to schedule Pods everywhere.
crazylion lee

Nmap: the Network Mapper - Free Security Scanner - 1 views

nmap.org

security network

shared by crazylion lee on 22 Nov 15 - No Cached
  • crazylion lee on 22 Nov 15
     
    "Nmap ("Network Mapper") is a free and open source (license) utility for network discovery and security auditing. Many systems and network administrators also find it useful for tasks such as network inventory, managing service upgrade schedules, and monitoring host or service uptime. Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics. It was designed to rapidly scan large networks, but works fine against single hosts. Nmap runs on all major computer operating systems, and official binary packages are available for Linux, Windows, and Mac OS X. In addition to the classic command-line Nmap executable, the Nmap suite includes an advanced GUI and results viewer (Zenmap), a flexible data transfer, redirection, and debugging tool (Ncat), a utility for comparing scan results (Ndiff), and a packet generation and response analysis tool (Nping)."
張 旭

Networking with overlay networks | Docker Documentation - 0 views

docs.docker.com/...network-tutorial-overlay

docker networking

shared by 張 旭 on 14 Sep 18 - No Cached
  • The manager host will function as both a manager and a worker, which means it can both run service tasks and manage the swarm.
  • connected together using an overlay network called ingress
  • each of them now has an overlay network called ingress and a bridge network called docker_gwbridge
  • ...7 more annotations...
  • The docker_gwbridge connects the ingress network to the Docker host’s network interface so that traffic can flow to and from swarm managers and workers
  • recommended that you use separate overlay networks for each application or group of applications which will work together
  • You don’t need to create the overlay network on the other nodes, beacause it will be automatically created when one of those nodes starts running a service task which requires it.
  • The default publish mode of ingress, which is used when you do not specify a mode for the --publish flag, means that if you browse to port 80 on manager, worker-1, or worker-2, you will be connected to port 80 on one of the 5 service tasks, even if no tasks are currently running on the node you browse to.
  • Even though overlay networks are automatically created on swarm worker nodes as needed, they are not automatically removed.
  • The -dit flags mean to start the container detached (in the background), interactive (with the ability to type into it), and with a TTY (so you can see the input and output).
  • alpine containers running ash, which is Alpine’s default shell rather than bash
張 旭

chaifeng/ufw-docker: To fix the Docker and UFW security flaw without disabling iptables - 0 views

github.com/ufw-docker

iptables docker

shared by 張 旭 on 13 Jul 22 - No Cached
  • It requires to disable docker's iptables function first, but this also means that we give up docker's network management function.
  • This causes containers will not be able to access the external network.
  • such as -A POSTROUTING ! -o docker0 -s 172.17.0.0/16 -j MASQUERADE. But this only allows containers that belong to network 172.17.0.0/16 can access outside.
  • ...13 more annotations...
  • Don't need to disable Docker's iptables and let Docker to manage it's network.
  • The public network cannot access ports that published by Docker.
  • In a very convenient way to allow/deny public networks to access container ports without additional software and extra configurations
  • Enable Docker's iptables feature. Remove all changes like --iptables=false , including configuration file /etc/docker/daemon.json
  • Modify the UFW configuration file /etc/ufw/after.rules
  • There may be some unknown reasons cause the UFW rules will not take effect after restart UFW, please reboot servers.
  • If we publish a port by using option -p 8080:80, we should use the container port 80, not the host port 8080
  • allow the private networks to be able to visit each other.
  • The following rules block connection requests initiated by all public networks, but allow internal networks to access external networks.
  • Since the UDP protocol is stateless, it is not possible to block the handshake signal that initiates the connection request as TCP does.
  • For GNU/Linux we can find the local port range in the file /proc/sys/net/ipv4/ip_local_port_range. The default range is 32768 60999
  • It not only exposes ports of containers but also exposes ports of the host.
  • Cannot expose services running on hosts and containers at the same time by the same command.
  • 張 旭 on 13 Jul 22
     
    "It requires to disable docker's iptables function first, but this also means that we give up docker's network management function."
張 旭

Installing Addons | Kubernetes - 0 views

kubernetes.io/...addons

kubernetes network networking

shared by 張 旭 on 25 Jan 23 - No Cached
  • Calico is a networking and network policy provider. Calico supports a flexible set of networking options so you can choose the most efficient option for your situation, including non-overlay and overlay networks, with or without BGP. Calico uses the same engine to enforce network policy for hosts, pods, and (if using Istio & Envoy) applications at the service mesh layer.
  • Cilium is a networking, observability, and security solution with an eBPF-based data plane. Cilium provides a simple flat Layer 3 network with the ability to span multiple clusters in either a native routing or overlay/encapsulation mode, and can enforce network policies on L3-L7 using an identity-based security model that is decoupled from network addressing. Cilium can act as a replacement for kube-proxy; it also offers additional, opt-in observability and security features.
  • CoreDNS is a flexible, extensible DNS server which can be installed as the in-cluster DNS for pods.
  • ...1 more annotation...
  • The node problem detector runs on Linux nodes and reports system issues as either Events or Node conditions.
張 旭

Overview of Virtual Private Cloud  |  VPC  |  Google Cloud - 0 views

cloud.google.com/...overview

google gcp cloud system networking

shared by 張 旭 on 09 Nov 18 - No Cached
  • a VPC network the same way you'd think of a physical network, except that it is virtualized within GCP.
  • VPC networks are logically isolated from each other in GCP.
  • The network connects the resources to each other and to the Internet.
  • 張 旭 on 09 Nov 18
     
    "a VPC network the same way you'd think of a physical network, except that it is virtualized within GCP."
張 旭

Azure 101: Networking Part 1 - Cloud Solution Architect - 0 views

blogs.msdn.microsoft.com/...azure-101-networking-part-1

microsoft azure networking network

shared by 張 旭 on 15 Jul 19 - No Cached
  • Virtual Private Gateways and it is these combined set of services that allow you to provide traffic flow to/from your Virtual Network and any external network, such as your On-Prem DataCenter.
  • No matter which version of the gateway you plan on implementing, there are three resources within Azure that you will need to implement and then connect to one of your Virtual Networks.
  • "Gateway Subnet". This is a specialized Subnet within your Virtual Network that can only be used for connecting Virtual Private Gateways to a VPN connection of some kind.
  • ...2 more annotations...
  • The Local Gateway is where you define the configuration of your external network's VPN access point with the most important piece being the external IP of that device so that Azure knows exactly how to establish the VPN connection.
  • The VPN Gateway is the Azure resource that you tie into your Gateway Subnet within your Virtual Network.
張 旭

Kubernetes Components | Kubernetes - 0 views

kubernetes.io/...components

kubernetes system

shared by 張 旭 on 17 May 21 - No Cached
  • A Kubernetes cluster consists of a set of worker machines, called nodes, that run containerized applications
  • Every cluster has at least one worker node.
  • The control plane manages the worker nodes and the Pods in the cluster.
  • ...29 more annotations...
  • The control plane's components make global decisions about the cluster
  • Control plane components can be run on any machine in the cluster.
  • for simplicity, set up scripts typically start all control plane components on the same machine, and do not run user containers on this machine
  • The API server is the front end for the Kubernetes control plane.
  • kube-apiserver is designed to scale horizontally—that is, it scales by deploying more instances. You can run several instances of kube-apiserver and balance traffic between those instances.
  • Kubernetes cluster uses etcd as its backing store, make sure you have a back up plan for those data.
  • watches for newly created Pods with no assigned node, and selects a node for them to run on.
  • Factors taken into account for scheduling decisions include: individual and collective resource requirements, hardware/software/policy constraints, affinity and anti-affinity specifications, data locality, inter-workload interference, and deadlines.
  • each controller is a separate process, but to reduce complexity, they are all compiled into a single binary and run in a single process.
  • Node controller
  • Job controller
  • Endpoints controller
  • Service Account & Token controllers
  • The cloud controller manager lets you link your cluster into your cloud provider's API, and separates out the components that interact with that cloud platform from components that only interact with your cluster.
  • If you are running Kubernetes on your own premises, or in a learning environment inside your own PC, the cluster does not have a cloud controller manager.
  • An agent that runs on each node in the cluster. It makes sure that containers are running in a Pod.
  • The kubelet takes a set of PodSpecs that are provided through various mechanisms and ensures that the containers described in those PodSpecs are running and healthy.
  • The kubelet doesn't manage containers which were not created by Kubernetes.
  • kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept.
  • kube-proxy maintains network rules on nodes. These network rules allow network communication to your Pods from network sessions inside or outside of your cluster.
  • kube-proxy uses the operating system packet filtering layer if there is one and it's available.
  • Kubernetes supports several container runtimes: Docker, containerd, CRI-O, and any implementation of the Kubernetes CRI (Container Runtime Interface).
  • Addons use Kubernetes resources (DaemonSet, Deployment, etc) to implement cluster features
  • namespaced resources for addons belong within the kube-system namespace.
  • all Kubernetes clusters should have cluster DNS,
  • Cluster DNS is a DNS server, in addition to the other DNS server(s) in your environment, which serves DNS records for Kubernetes services.
  • Containers started by Kubernetes automatically include this DNS server in their DNS searches.
  • Container Resource Monitoring records generic time-series metrics about containers in a central database, and provides a UI for browsing that data.
  • A cluster-level logging mechanism is responsible for saving container logs to a central log store with search/browsing interface.
crazylion lee

netboot.xyz - 0 views

netboot.xyz

netboot ipxe network boot linux

shared by crazylion lee on 27 Feb 16 - No Cached
  • crazylion lee on 27 Feb 16
     
    "The DHCP bootloaders will automatically get a network address if you have DHCP on your network while the static bootloaders will prompt you for network information. SHA256 checksums are generated during each build of iPXE and are located here. You can also view the scripts that are embedded into the images here. "
張 旭

What Is Amazon VPC? - Amazon Virtual Private Cloud - 0 views

docs.aws.amazon.com/...VPC_Introduction.html

aws networking

shared by 張 旭 on 31 Jul 18 - No Cached
  • to allow an instance in your VPC to initiate outbound connections to the internet but prevent unsolicited inbound connections from the internet, you can use a network address translation (NAT) device for IPv4 traffic
  • A NAT device has an Elastic IP address and is connected to the internet through an internet gateway.
  • By default, each instance that you launch into a nondefault subnet has a private IPv4 address, but no public IPv4 address, unless you specifically assign one at launch, or you modify the subnet's public IP address attribute.
  • ...11 more annotations...
  • Amazon VPC is the networking layer for Amazon EC2.
  • A virtual private cloud (VPC) is a virtual network dedicated to your AWS account. It is logically isolated from other virtual networks in the AWS Cloud.
  • Instances can connect to the internet over IPv6 through an internet gateway
  • IPv6 traffic is separate from IPv4 traffic; your route tables must include separate routes for IPv6 traffic.
  • You can optionally connect your VPC to your own corporate data center using an IPsec AWS managed VPN connection, making the AWS Cloud an extension of your data center.
  • A VPN connection consists of a virtual private gateway attached to your VPC and a customer gateway located in your data center.
  • A virtual private gateway is the VPN concentrator on the Amazon side of the VPN connection. A customer gateway is a physical device or software appliance on your side of the VPN connection.
  • AWS PrivateLink is a highly available, scalable technology that enables you to privately connect your VPC to supported AWS services, services hosted by other AWS accounts (VPC endpoint services)
  • Traffic between your VPC and the service does not leave the Amazon network
  • To use AWS PrivateLink, create an interface VPC endpoint for a service in your VPC. This creates an elastic network interface in your subnet with a private IP address that serves as an entry point for traffic destined to the service.
  • create your own AWS PrivateLink-powered service (endpoint service) and enable other AWS customers to access your service.
crazylion lee

Gaffer on Games | Game Networking - 0 views

gafferongames.com/etworking-for-game-programmers

game networking programming

shared by crazylion lee on 30 Jan 17 - No Cached
  • crazylion lee on 30 Jan 17
     
    "Game Networking"
張 旭

VPCs and Subnets - Amazon Virtual Private Cloud - 0 views

docs.aws.amazon.com/...VPC_Subnets.html

aws networking amazon cloud

shared by 張 旭 on 31 Jul 18 - No Cached
  • you must specify a range of IPv4 addresses for the VPC in the form of a Classless Inter-Domain Routing (CIDR) block
  • A VPC spans all the Availability Zones in the region
  • add one or more subnets in each Availability Zone.
  • ...19 more annotations...
  • Each subnet must reside entirely within one Availability Zone and cannot span zones.
  • Availability Zones are distinct locations that are engineered to be isolated from failures in other Availability Zones
  • If a subnet's traffic is routed to an internet gateway, the subnet is known as a public subnet.
  • If a subnet doesn't have a route to the internet gateway, the subnet is known as a private subnet.
  • If a subnet doesn't have a route to the internet gateway, but has its traffic routed to a virtual private gateway for a VPN connection, the subnet is known as a VPN-only subnet.
  • By default, all VPCs and subnets must have IPv4 CIDR blocks—you can't change this behavior.
  • The allowed block size is between a /16 netmask (65,536 IP addresses) and /28 netmask (16 IP addresses).
  • The first four IP addresses and the last IP address in each subnet CIDR block are not available for you to use
  • The allowed block size is between a /28 netmask and /16 netmask
  • The CIDR block must not overlap with any existing CIDR block that's associated with the VPC.
  • Each subnet must be associated with a route table
  • Every subnet that you create is automatically associated with the main route table for the VPC
  • Security groups control inbound and outbound traffic for your instances
  • network ACLs control inbound and outbound traffic for your subnets
  • each subnet must be associated with a network ACL
  • You can create a flow log on your VPC or subnet to capture the traffic that flows to and from the network interfaces in your VPC or subnet.
  • A VPC peering connection enables you to route traffic between the VPCs using private IP addresses
  • you cannot create a VPC peering connection between VPCs that have overlapping CIDR blocks
  • recommend that you create a VPC with a CIDR range large enough for expected future growth, but not one that overlaps with current or expected future subnets anywhere in your corporate or home network, or that overlaps with current or future VPCs
張 旭

Let's Encrypt & Docker - Træfik - 0 views

docs.traefik.io/...docker-and-lets-encrypt

traefik docker networking proxy

shared by 張 旭 on 19 Sep 18 - No Cached
  • automatically discover any services on the Docker host and let Træfik reconfigure itself automatically when containers get created (or shut down) so HTTP traffic can be routed accordingly.
  • use Træfik as a layer-7 load balancer with SSL termination for a set of micro-services used to run a web application.
  • Docker containers can only communicate with each other over TCP when they share at least one network.
  • ...15 more annotations...
  • Docker under the hood creates IPTable rules so containers can't reach other containers unless you'd want to
  • Træfik can listen to Docker events and reconfigure its own internal configuration when containers are created (or shut down).
  • Enable the Docker provider and listen for container events on the Docker unix socket we've mounted earlier.
  • Enable automatic request and configuration of SSL certificates using Let's Encrypt. These certificates will be stored in the acme.json file, which you can back-up yourself and store off-premises.
  • there isn't a single container that has any published ports to the host -- everything is routed through Docker networks.
  • Thanks to Docker labels, we can tell Træfik how to create its internal routing configuration.
  • container labels and service labels
  • With the traefik.enable label, we tell Træfik to include this container in its internal configuration.
  • tell Træfik to use the web network to route HTTP traffic to this container.
  • Service labels allow managing many routes for the same container.
  • When both container labels and service labels are defined, container labels are just used as default values for missing service labels but no frontend/backend are going to be defined only with these labels.
  • In the example, two service names are defined : basic and admin. They allow creating two frontends and two backends.
  • Always specify the correct port where the container expects HTTP traffic using traefik.port label.
  • all containers that are placed in the same network as Træfik will automatically be reachable from the outside world
  • With the traefik.frontend.auth.basic label, it's possible for Træfik to provide a HTTP basic-auth challenge for the endpoints you provide the label for.
張 旭

探索 Docker bridge 的正确姿势，亲测有效！ | DaoCloud - 1 views

blog.daocloud.io/docker-bridge

docker networking system

shared by 張 旭 on 10 Mar 17 - No Cached
  • Docker bridge 和 Linux bridge 二者，初看如出一辙，再看又相去甚远
  • Linux bridge 模式下，Linux Kernel 会创建出一个虚拟网桥 ，用以实现主机网络接口与虚拟网络接口间的通信
  • Linux bridge 像一台虚拟交换机
  • ...15 more annotations...
  • Docker Daemon 会创建出一个名为 docker0 的虚拟网桥 ，用来连接宿主机与容器，或者连接不同的容器
  • veth pair 技术的特性可以保证无论哪一个 veth 接收到网络报文，都会无条件地传输给另一方
  • 在桥接模式下，Docker Daemon 将 veth0 附加到 docker0 网桥上，保证宿主机的报文有能力发往 veth0。
  • 将 veth1 添加到 Docker 容器所属的网络命名空间[注释2]，保证宿主机的网络报文若发往 veth0 可以立即被 veth1 收到
  • NATP 包含两种转换方式：SNAT 和 DNAT
  • 目的 NAT (Destination NAT，DNAT): 修改数据包的目的地址
  • 容器的 IP 与端口对外都是不可见的
  • 数据包的目的地址为宿主机的 ip 和端口
  • 将数据包发送附加到 docker0 网桥上的 veth0 接口，veth0 接口再将数据包发送给容器内部的 veth1 接口，容器接收数据包并作出响应
  • 源 NAT (Source NAT，SNAT): 修改数据包的源地址
  • 宿主机上的 docker0 网桥发现数据包的目的地址为外界的 IP 和端口，便会将数据包转发给 eth0 ，并从 eth0 发出去。由于存在 SNAT 规则，会将数据包的源地址转换为宿主机的 ip 和端口
  • Docker 容器对外是不可见的
  • veth pair是用于不同network namespace间进行通信的方式，veth pair 将一个 network namespace 数据发往另一个 network namespace 的 veth
  • 网络命名空间是用于隔离网络资源（/proc/net、IP 地址、网卡、路由等）
  • NAT 为网络地址转换（Network Address Translation）的缩写
張 旭

Service | Kubernetes - 0 views

kubernetes.io/...service

kubernetes networking service ingress

shared by 張 旭 on 14 Apr 21 - No Cached
  • Each Pod gets its own IP address
  • Pods are nonpermanent resources.
  • Kubernetes Pods are created and destroyed to match the state of your cluster
  • ...23 more annotations...
  • In Kubernetes, a Service is an abstraction which defines a logical set of Pods and a policy by which to access them (sometimes this pattern is called a micro-service).
  • The set of Pods targeted by a Service is usually determined by a selector
  • If you're able to use Kubernetes APIs for service discovery in your application, you can query the API server for Endpoints, that get updated whenever the set of Pods in a Service changes.
  • A Service in Kubernetes is a REST object, similar to a Pod.
  • The name of a Service object must be a valid DNS label name
  • Kubernetes assigns this Service an IP address (sometimes called the "cluster IP"), which is used by the Service proxies
  • A Service can map any incoming port to a targetPort. By default and for convenience, the targetPort is set to the same value as the port field.
  • The default protocol for Services is TCP
  • As many Services need to expose more than one port, Kubernetes supports multiple port definitions on a Service object. Each port definition can have the same protocol, or a different one.
  • Because this Service has no selector, the corresponding Endpoints object is not created automatically. You can manually map the Service to the network address and port where it's running, by adding an Endpoints object manually
  • Endpoint IP addresses cannot be the cluster IPs of other Kubernetes Services
  • Kubernetes ServiceTypes allow you to specify what kind of Service you want. The default is ClusterIP
  • ClusterIP: Exposes the Service on a cluster-internal IP.
  • NodePort: Exposes the Service on each Node's IP at a static port (the NodePort). A ClusterIP Service, to which the NodePort Service routes, is automatically created. You'll be able to contact the NodePort Service, from outside the cluster, by requesting <NodeIP>:<NodePort>.
  • LoadBalancer: Exposes the Service externally using a cloud provider's load balancer
  • ExternalName: Maps the Service to the contents of the externalName field (e.g. foo.bar.example.com), by returning a CNAME record with its value. No proxying of any kind is set up.
  • You can also use Ingress to expose your Service. Ingress is not a Service type, but it acts as the entry point for your cluster.
  • If you set the type field to NodePort, the Kubernetes control plane allocates a port from a range specified by --service-node-port-range flag (default: 30000-32767).
  • The default for --nodeport-addresses is an empty list. This means that kube-proxy should consider all available network interfaces for NodePort.
  • you need to take care of possible port collisions yourself. You also have to use a valid port number, one that's inside the range configured for NodePort use.
  • Service is visible as <NodeIP>:spec.ports[*].nodePort and .spec.clusterIP:spec.ports[*].port
  • Choosing this value makes the Service only reachable from within the cluster.
  • NodePort: Exposes the Service on each Node's IP at a static port
crazylion lee

Artificial Neural Networks for Beginners » Loren on the Art of MATLAB - 0 views

blogs.mathworks.com/...-neural-networks-for-beginners

machine-learning learning deep

shared by crazylion lee on 16 Oct 15 - No Cached
  • crazylion lee on 16 Oct 15
     
    "Deep Learning is a very hot topic these days especially in computer vision applications and you probably see it in the news and get curious. Now the question is, how do you get started with it? Today's guest blogger, Toshi Takeuchi, gives us a quick tutorial on artificial neural networks as a starting point for your study of deep learning."
snow9816

CentOS 出現 connect: Network is unreachable 解決方法 | IT達人 - 0 views

www.itmaster.tw/?p=10837

network linux system

shared by snow9816 on 01 Sep 16 - No Cached
  • /etc/sysconfig/network-scripts/ifcfg-eth0
  • service network restart
張 旭

What's the Docker Swarm "-advertise-addr"? - Blog | BoxBoat - 0 views

boxboat.com/...ts-docker-swarm-advertise-addr

docker swarm networking

shared by 張 旭 on 11 Sep 18 - No Cached
  • To put it simply, the --advertise-addr is the address other nodes in the Docker swarm use to connect into your node.
  • a port number which defaults to 2377
  • The --listen-addr is the address that the swarm service listens on for incoming connections.
  • ...2 more annotations...
  • The default for --listen-addr is to listen on all interfaces on TCP port 2377 (0.0.0.0:2377)
  • Depending on your network architecture, you may want your swarm management interface only accessible on a management network that could be separate from a data and/or public network that are each attached to a physical server.
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