· ☕ 3 分钟
https://istio.io/latest/docs/ops/configuration/traffic-management/tls-configuration/
Sidecars Sidecar traffic has a variety of associated connections. Let’s break them down one at a time.
Sidecar proxy network connections
External inbound traffic This is traffic coming from an outside client that is captured by the sidecar. If the client is inside the mesh, this traffic may be encrypted with Istio mutual TLS. By default, the sidecar will be configured to accept both mTLS and non-mTLS traffic, known as PERMISSIVE mode.
· ☕ 1 分钟
https://istio.io/v1.4/docs/tasks/security/authentication/mtls-migration/
Ensure that your cluster is in PERMISSIVE mode before migrating to mutual TLS. Run the following command to check:
1 2 3 4 5 6 $ kubectl get meshpolicy default -o yaml ... spec: peers: - mtls: mode: PERMISSIVE In PERMISSIVE mode, the Envoy sidecar relies on the ALPN value istio to decide whether to terminate the mutual TLS traffic. If your workloads (without Envoy sidecar) have enabled mutual TLS directly to the services with Envoy sidecars, enabling PERMISSIVE mode may cause these connections to fail.
· ☕ 2 分钟
SPIFFE https://spiffe.io/docs/latest/spiffe-about/overview/
https://spiffe.io/docs/latest/spiffe-about/spiffe-concepts/
old school Official SPIFFE method:
https://blog.envoyproxy.io/securing-the-service-mesh-with-spire-0-3-abb45cd79810
Workload A workload is a single piece of software, deployed with a particular configuration for a single purpose; it may comprise multiple running instances of software, all of which perform the same task. The term “workload” may encompass a range of different definitions of a software system, including:
A web server running a Python web application, running on a cluster of virtual machines with a load-balancer in front of it.
· ☕ 2 分钟
x-forwarded-client-cert https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_conn_man/headers#x-forwarded-client-cert
x-forwarded-client-cert (XFCC) is a proxy header which indicates certificate information of part or all of the clients or proxies that a request has flowed through, on its way from the client to the server. A proxy may choose to sanitize/append/forward the XFCC header before proxying the request.
The XFCC header value is a comma (",") separated string. Each substring is an XFCC element, which holds information added by a single proxy.
· ☕ 2 分钟
https://istio.io/latest/docs/ops/common-problems/network-issues/#double-tls
Double TLS (TLS origination for a TLS request) When configuring Istio to perform TLS origination, you need to make sure that the application sends plaintext requests to the sidecar, which will then originate the TLS.
TLS Origination
TLS origination occurs when an Istio proxy (sidecar or egress gateway) is configured to accept unencrypted internal HTTP connections, encrypt the requests, and then forward them to HTTPS servers that are secured using simple or mutual TLS.
· ☕ 1 分钟
How Does the CPU Manager Work? When CPU manager is enabled with the “static” policy, it manages a shared pool of CPUs. Initially this shared pool contains all the CPUs in the compute node. When a container with integer CPU request in a Guaranteed pod is created by the Kubelet, CPUs for that container are removed from the shared pool and assigned exclusively for the lifetime of the container. Other containers are migrated off these exclusively allocated CPUs.
· ☕ 1 分钟
注意：kubelet修改cpu_manager策略配置，一定要停掉kubelet服务，并删除/var/lib/kubelet/cpu_manager_state 文件，再重启kubelet，否则会导致kubelet服务重启失败。
kubelet的快照文件:
cpu_manager_state：CPU管理器快照文件，包含cpu分配策略和已分配pod的cpuset信息
device-plugins/kubelet_internal_checkpoint：deviceplugin的快照信息，这里关注测试numa亲和性分配相关的TOPO分配信息
Ref. http://bingerambo.com/posts/2020/12/k8s%E5%9F%BA%E4%BA%8Enuma%E4%BA%B2%E5%92%8C%E6%80%A7%E7%9A%84%E8%B5%84%E6%BA%90%E5%88%86%E9%85%8D%E7%89%B9%E6%80%A7%E6%B5%8B%E8%AF%95/
· ☕ 2 分钟
Memory Manager Goals 保证最少 NUMA Node 去满足 POD 的内存需求: Offer guaranteed memory (and hugepages) allocation over a minimum number of NUMA nodes for containers (within a pod).
长远是让pod中的所有 container 运行在尽量少的 NUMA NODE 中： Guaranteeing the affinity of memory and hugepages to the same NUMA node for the whole group of containers (within a pod). This is a long-term goal which will be achieved along with PR #1752 and the implementation of hintprovider.
· ☕ 3 分钟
K8s Memory Manager Requriement Your Kubernetes server must be at or later than version v1.21. To check the version, enter kubectl version.
To align memory resources with other requested resources in a Pod Spec:
the CPU Manager should be enabled and proper CPU Manager policy should be configured on a Node. See control CPU Management Policies; the Topology Manager should be enabled and proper Topology Manager policy should be configured on a Node.
· ☕ 2 分钟
Topology Manager Scopes and Policies Topology Manager provides two distinct knobs: scope and policy.
The scope defines the granularity at which you would like resource alignment to be performed (e.g. at the pod or container level). And the policy defines the actual strategy used to carry out the alignment (e.g. best-effort, restricted, single-numa-node, etc.).
Topology Manager Scopes The Topology Manager can deal with the alignment of resources in a couple of distinct scopes:
· ☕ 1 分钟
kubectl debug https://kubernetes.io/docs/tasks/debug-application-cluster/debug-running-pod/#ephemeral-container
https://towardsdatascience.com/the-easiest-way-to-debug-kubernetes-workloads-ff2ff5e3cc75
1 2 3 kubectl explain pod.spec.ephemeralContainers kubectl debug -it ephemeral-demo --image=busybox --target=ephemeral-demo Process Namespace Sharing https://towardsdatascience.com/the-easiest-way-to-debug-kubernetes-workloads-ff2ff5e3cc75
kubectl debug -it some-app –image=busybox –share-processes –copy-to=some-app-debug
· ☕ 1 分钟
➜ 2305 pidstat -t -p 2305 1 Linux 5.4.0-74-generic (labile-T30) 2021年06月24日 _x86_64_ (2 CPU) 18时37分39秒 UID TGID TID %usr %system %guest %wait %CPU CPU Command 18时37分40秒 64055 2305 - 1.00 2.00 14.00 3.00 17.00 1 qemu-system-x86 18时37分40秒 64055 - 2305 1.00 1.00 0.00 3.00 2.00 1 |__qemu-system-x86 18时37分40秒 64055 - 2307 0.00 0.00 0.00 0.00 0.00 0 |__qemu-system-x86 18时37分40秒 64055 - 2312 0.00 0.00 0.00 0.00 0.00 0 |__IO mon_iothread 18时37分40秒 64055 - 2313 0.