1. What Is EnvoyFilter EnvoyFilter is a CRD resource in Istio that allows users to modify Envoy’s configuration to satisfy their customization needs for different scenarios. 1 2 3 4 5 6 7 8 9 kubectl get envoyfilter -A NAMESPACE NAME AGE istio-system add-request-id-into-ingressgateway 54d istio-system compression-gzip 18d istio-system custom-access-log 3d istio-system ingressgateway-settings 52d istio-system preserve-request-header-us-test-ingress-gateway 95d istio-system preserve-x-request-id 54d When using Istio, you will usually end up using at least a few EnvoyFilters.

1. Check the PCI Interface Device Use lspci to check whether the device is already installed. 1 2 3 lspci |grep storage d8:00.0 Mass storage controller: Shannon Systems Device 2275 Here a Shannon Systems device shows up, which means the SSD is already installed. 1 2 3 4 5 6

1. Symptoms The business side reported that the API of application app-a was slow. Looking at the logs, one particular Pod was slow, and deleting that Pod so it moved to another node fixed it. From the monitoring metrics you can see that the Pod’s CPU usage did indeed spike sharply.

1. Subnet Management by kube-controller-manager kube-controller-manager has many controllers; the one related to Pod IP is NodeIpamController. The NodeIpamController mainly manages the podcidr of nodes: when a new node joins the cluster, it allocates a subnet to that node; when a node is deleted, it reclaims the subnet. The subnets

1. What Is an Ops Tool https://www.chenshaowen.com/ops/ is one of the tools I use most often in day-to-day operations. To operate on machines, I can reuse my previous scripts and perform operations in bulk. To operate on clusters, I can reuse my previous scripts and operate machines without logging into the nodes.