Hashicorp Vault: Diagnose Vault server

这是Vault 1.8 的新功能，能帮助在Vault server启动前先诊断状况，例如: OS open file limit, OS disk usage, Vault server configuration等等，诊断状态分为三种:
．success: 检查成功。
．warning: 检查通过，但有潜在的问题需要排除。
．failure: 检查失败。

用法

$ vault operator diagnose -config vault-server.hcl

Vault v1.8.2 (4eg99f1rthet5467i9a356uyk43yjutyfg456)

Results:
[ warning ] Vault Diagnose
  [ warning ] Check Operating System
    [ success ] Check Open File Limits: Open file limits are set to 655350.
    [ success ] Check Disk Usage: / usage ok.
    [ warning ] Check Disk Usage: /dev is %!d(float64=100) percent full.
      It is recommended to have more than five percent of the partition free.
    [ success ] Check Disk Usage: /System/Volumes/VM usage ok.
    [ success ] Check Disk Usage: /System/Volumes/Preboot usage ok.
    [ success ] Check Disk Usage: /System/Volumes/Update usage ok.
    [ success ] Check Disk Usage: /System/Volumes/Data usage ok.
    [ warning ] Check Disk Usage: /System/Volumes/Data/home has %d bytes full.
      It is recommended to have at least 1 GB of space free per partition.
  [ success ] Parse Configuration
  [ success ] Check Storage
    [ success ] Create Storage Backend
    [ success ] Check Storage Access
  [ skipped ] Check Service Discovery: No service registration configured.
  [ success ] Create Vault Server Configuration Seals
  [ skipped ] Check Transit Seal TLS: No transit seal found in seal configuration.
  [ success ] Create Core Configuration
    [ success ] Initialize Randomness for Core
  [ success ] HA Storage
    [ success ] Create HA Storage Backend
    [ skipped ] Check HA Consul Direct Storage Access: No HA storage stanza is configured.
  [ success ] Determine Redirect Address
  [ success ] Check Cluster Address: Cluster address is logically valid and can be found.
  [ success ] Check Core Creation
  [ skipped ] Check For Autoloaded License: License check will not run on OSS Vault.
  [ warning ] Start Listeners
    [ warning ] Check Listener TLS: Listener at address 10.x.x.x:8200: TLS is disabled in a listener config stanza.
    [ success ] Create Listeners
  [ skipped ] Check Autounseal Encryption: Skipping barrier encryption test. Only supported for auto-unseal.
  [ success ] Check Server Before Runtime
  [ success ] Finalize Shamir Seal