kubernetes中正strace etcd

strace The full name is System Call Tracing,Meaning it's a process,Acts like a sidecar on the system call interface,Every system call is logged.这篇 Medium 文章to how most people use it in practice strace A very simple explanation is given,If anyone is interested in details,这篇文章A thorough walkthrough will be given.归根结底,您可以在 strace There are many parameters used in ,And it all depends on the situation.为了演示,We will be debugging Kubernetes Use the usual ones for operation.

An example would be to see if we can read stored in etcd 中的秘密.为了实现这一点,我们需要知道 etcd 正在运行的进程 ID

$ ps aux | grep etcd

从上面的结果来看,第一个进程 ID will be our goal,Because the second process is kube-apiserver,The third is what we just implemented“grep”

sudo strace -p 4295

We should see a lot of operations listed.从这里,We can go to the process directory and see what it contains.

- sudo su
- cd /proc/4295/fd
- ls -l | grep 7

此时,目录“7”seems to contain K8s 需要的信息.We can create a simple secret and try to find the value in it.

- kubectl create secret generic credit-card --from-literal ssecret=1111222233334444
#Make sure you are still in directory /proc/4295/fd. 
#"-A10" and "-B10" mean show 10 lines before and after the searching string.
- cat 7 | strings | grep 1111222233334444 -A10 -B10