9 | Networking | Best-General

9.7 | Ingress-2 | Ingress-Controller 1) Main Components [4]? What K8s Objects are these? 2) What are (Cluster)Roles/RoleBindings needed for? 3) In the Deployment, what all must you specify [1+2+2+2] 4) What are some examples of Nginx config args [3]? (NOT CRITICAL)

1) > a) Deployment - Main Controller > b) ConfigMap - Nginx Configuration > c) Service - Exposing Deployment > d) ServiceAccount - Allowing Cluster-Watching ==> Has Roles/RoleBindings/ClusterRoles 2) ServiceAccount Authentication 3) All in - spec.template.spec.containers[]... > a) Nginx Startup - ==> args = ./nginx-ingress-controller > b) Nginx Configuration Args - ConfigMap > c) serviceAccountName - ServiceAccount > d) Pod's Name/Namespace ==> env > e) Http/Https Ports 4) err-log-path, keep-alive, ssl-protocols

9.6 | DNS-3 | CoreDNS 1) CoreDNS Primary Components [3]? 2) Where is CoreDNS configuration stored? How is it passed in? 3) Who programs the kube-dns service IP into Pods? 4) Where can you specify the "kube-dns"'s IP? 5) Regarding the Core file, what do the following keys indicate? > a) "kubernetes" > b) "pod" > c) "proxy" 6) CMD. How can you access the Corefile?

1) > a) coredns - Deployment > b) kube-dns - Service > c) coredns - Configmap 2) "/etc/coredns/Corefile" (INTRA-POD). CM/coredns 3) Kubelet 4) "/var/lib/kubelet/config.yaml" file 5) > a) Cluster's TLD > b) Enable Pod Record Creation > c) Additional nameservers (for Records DNS can't resolve) 6) kg cm/coredns -n=kube-system -oyaml

9.1 ==== Docker, CNI==== 1) What IP does Docker Bridge Network run on by default? 2) What is an identifying characteristic of Bridge/Interface Pairs? 3) When doing "docker run -p 8080:80 nginx", what are the ports referring to [BLANK_A:BLANK_B]? 4) What is the above process called? 5) Does Docker support CNI? If not, what does it support? 6) How does this affect in the real world (ie. "docker run"...)?

1) 172.17.0.0 2) Odd/Even - (Bridge=Odd, Container=Even) 3) HOST-PORT: CONTAINER-PORT 4) NAT (Network Address Translation) 5 NO. CNM (Container-Network Model) 6) Requires manually adding v. "--network" flag

9.7 | Ingress-1 | General 1) NodePort SVC - Port-Range? 2) General Definition? (Layer specifically?) 3) What are the primary components [2]? 4) Controller examples [6]? Which are officially K8s-Supported [2]?

1) > 30000 2) K8s Built-In L7 Load-Balancer 3) > a) Controller - Reverse-Proxy > b) Resources - "Rules" 4) Nginx, Contour, HAProxy, Traefik, Istio, GCE ==> GCE, Nginx

9.1 =====CNI | EXAMPLES===== Can you list some CNI plugins examples for the following... 1) Out-Of-The-Box [2+3]? 2) 3rd-Party [CC+WF+VR]? 3) IPAM [2]? What does IPAM stand for?

1) BRIDGE, WINDOWS, VLAN, IPVLAN, MACVLAN 2) Calico, Cilium, Weave, Flannel, VMWare NSX, Redhat InfoBlox 3) DHCP, host-local 4) IP-Address Management

9.2 =====IPAM===== 1) Who/What assigns IP addresses to Pods? Examples[2]? 2) Where can you specify ^^ Entity for dynamic IP Address assignment? 3) By Default, what subnet does Weave allocate for Pod IPs? 4) How many IP's is ^, and how are these split amongst Weave-Peers?

1) CNI-Plugin. host-local, DHCP 2) /etc/cni/net.d/net-script.conf 3) 10.32.0.0/12 4) 1,000,000 IP's - Split equally amongst peers

9.1 =====CNI | IN-DEPTH===== The CNI states what responsibilities for each of the following... 1) Container-Runtime [3+2]? 2) Plugin [2+2]?

1) Container-Runtime [CR] | Responsible for > a) Namespace Creation - (Network NS) > b) Network Identification - That Container attaches to > c) JSON Format - Of Network Configuration Must invoke Network Plugin (bridge) on... > d) Container ADD > e) Container DELETE 2) Plugin | Responsible for > a) CLI-Arg Support - ADD/DEL/CHECK > b) Parameter Support - Container-Id/Network ns, etc. > c) IP Address Assignment - To PODs > d) Result Formatting - Specific Format

9.6 DNS-2 | K8s-General: 1) What does the K8s built-in DNS server do? What is this process called? 2) What all composes a FQDN [4]? 3) What is the typical default cluster-domain? 4) What's the FQDN for svc "web-service" in "apps" NS w/ IP 10.107.37.188? 5) What's the FQDN for pod "web-app" in "apps" NS w/ IP 10.244.1.5?

1) Creates Name-IP Mappings. Name Resolution 2) HostName-NS-Type-Root 3) cluster-local 4) web-service.apps.svc.cluster-local 5) 10-244-1-5.apps.pod.cluster-local

9.2 =====WEAVE-CNI===== 1) In general what does Weave do? 2) What does a Weave Agent/Peer hold? 3) Can a pod be attached to multiple bridge networks? If so, what are some examples? 4) How can weave be deployed [2]? 5) How are Weave-Peers deployed on a K8s Cluster?

1) Deploys an agent to every k8s node in the cluster 2) Topology of the entire cluster 3) Yes. Ex. Weave-Bridge && Docker-Bridge 4) > a) Services/Daemons - Via Daemonset > b) Pods - (If K8s is setup already) 5) As a Daemonset on each Node in the cluster.

9.2 =====POD-NETWORKING-GENERAL===== 1) What does the K8s Pod Network Model entail[3]? 2) For Intra-Node Pod Communication, what are the main steps [2]? 3) For Inter-Node Pod Communication, what are the main steps [1]?

1) Every Pod should... > a) Have an IP Address > b) Reach all other Pods - Within SAME Node > c) Reach all Pods - On OTHER Nodes WITHOUT NAT 2) > b) Create/Setup Bridge Network > c) Run Script - For Connecting New Containers to Bridge 3) Create Router that Maps all Bridge-IPs to Node IP's.

9.2 =====K8S-CNI===== 1) In what k8s object is CNI specified? 2) What are the CMDline Options[3]? 3) In what directory can you find CNI plugins? 4) Where is the bridge config file located? 5) In the Bridge Config file, what does "isGateway" field entail? 6) In the Bridge Config file, what does "ipMasq" field entail? 7) Command to find network plugin currently configured for Kubernetes[2]?

1) Kubelet 2) --network-plugin=cni --cni-bin-dir=/opt/cni/bin --cni-conf-dir=/etc/cni/net.d 3) "/opt/cni/bin" 4) "/etc/cni/net.d" 5) Whether or not Bridge Network should have an IP assigned to it (or not) 6) If NAT rules should be added for IPMasquarade 7) > a) cat /var/lib/kubelet/kubeadm-flags.env > b) ps -aux | grep kubelet | grep network-plugin

Can you explain the following network-related objects.... 1) Switch (What address does it use, & what Network Layer?) 2) Router (What address does it use, & what Network Layer?) 3) Gateway

1) Multiport network bridge. Uses.... - MAC addresses to forward data @ DL (2) Layer 2) Network Bridge. Offers NAT. Uses.... - IP Addresses to forward data @ Network (3) Layer 3) Gateway - Route that a Router uses to reach external IP's

How many args should you have for ingress pod?

8

9.1 === Docker, CNI==== 1) What networking types are available in Docker [4]? 2) Can you also list the commands?

====================TYPES========================= > a) NONE - Only STDIN/STDOUT communication > b) HOST - Uses host's network to run. ==> Communication - https://[HOST-IP]:[CONT-PORT] > c) CONTAINER - Uses another container's network > d) BRIDGE (Default) - Uses Internal Bridge Network ===================COMMANDS======================= > a) "docker run --network none [IMG]" > b) "docker run --network host [IMG]" > c) "docker run --network container:[CONT] [IMG]" > d) "docker run [IMG]" // Default

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Has all 9.1/9.2