在Ubuntu18.04 LTS服务器版中发现报错：
“sshd error:could not load host key”(无法加载主机密钥)。

Sep 29 16:01:28 lab sshd[1088]: error: key_load_private: invalid format
Sep 29 16:01:28 lab sshd[1088]: error: key_load_public: invalid format
Sep 29 16:01:28 lab sshd[1088]: error: Could not load host key: /etc/ssh/ssh_host_rsa_key
Sep 29 16:01:28 lab sshd[1088]: error: key_load_private: invalid format
Sep 29 16:01:28 lab sshd[1088]: error: key_load_public: invalid format
Sep 29 16:01:28 lab sshd[1088]: error: Could not load host key: /etc/ssh/ssh_host_ecdsa_key
Sep 29 16:01:28 lab sshd[1088]: error: key_load_private: invalid format
Sep 29 16:01:28 lab sshd[1088]: error: key_load_public: invalid format
Sep 29 16:01:28 lab sshd[1088]: error: Could not load host key: /etc/ssh/ssh_host_ed25519_key
Sep 29 16:01:28 lab sshd[1088]: fatal: No supported key exchange algorithms [preauth]

如何修复“sshd错误：无法加载主机密钥”

首先备份ssh config文件夹。

sudo cp -rvf /etc/sshd ~/sshd-backup

删除ssh主机密钥。

sudo rm /etc/ssh/ssh*key

重新生成ssh密钥

sudo dpkg-reconfigure openssh-server

重新启动openssh服务器

sudo systemctl restart ssh