我正在尝试将 unbound 设置为我的 DNS 解析器，但它似乎unbound在启动后立即终止。日志中似乎没有任何内容表明为什么会发生这种情况。该服务器上安装了 pi-hole，并且还在运行 Apache 网络服务器。
配置文件与pi-hole 的文档中的完全相同，只是将logfile其更改为/var/log/unbound/unbound.log并将详细程度设置为2.
开始unbound使用service unbound start将导致systemd尝试一次又一次地开始不受约束。
Jan 28 15:58:51 srv01 systemd[1]: unbound.service: Main process exited, code=killed, status=9/KILL
Jan 28 15:58:51 srv01 systemd[1]: unbound.service: Failed with result 'signal'.
Jan 28 15:58:51 srv01 systemd[1]: Failed to start Unbound DNS server.
Jan 28 15:58:51 srv01 systemd[1]: unbound.service: Service hold-off time over, scheduling restart.
etc..
在前台运行它会显示：
[1584217278] unbound[31341:0] notice: Start of unbound 1.6.7.
[1584217278] unbound[31341:0] debug: increased limit(open files) from 1024 to 4140
[1584217278] unbound[31341:0] debug: creating udp4 socket 127.0.0.1 5353
[1584217278] unbound[31341:0] debug: creating tcp4 socket 127.0.0.1 5353
[1584217278] unbound[31341:0] debug: creating tcp4 socket 127.0.0.1 8953
[1584217278] unbound[31341:0] debug: setup SSL certificates
[1584217278] unbound[31341:0] warning: did not exit gracefully last time (30708)
[1584217278] unbound[31341:0] debug: chdir to /etc/unbound
[1584217278] unbound[31341:0] debug: drop user privileges, run as unbound
[1584217278] unbound[31341:0] debug: switching log to /var/log/unbound/unbound.log
Killed
上次运行的日志文件输出为：
[1584216438] unbound[30708:0] debug: module config: "subnetcache validator iterator"
[1584216438] unbound[30708:0] notice: init module 0: subnet
[1584216438] unbound[30708:0] debug: subnet: option registered (8)
[1584216438] unbound[30708:0] notice: init module 1: validator
[1584216438] unbound[30708:0] debug: reading autotrust anchor file /var/lib/unbound/root.key
[1584216438] unbound[30708:0] info: trust point . : 1
[1584216438] unbound[30708:0] info: assembled 0 DS and 2 DNSKEYs
[1584216438] unbound[30708:0] info: DNSKEY:: . 172800 IN DNSKEY 257 3 8 <redacted> ;{id = 20326 (ksk), size = 2048b}
[1584216438] unbound[30708:0] info: DNSKEY:: . 172800 IN DNSKEY 257 3 8 <redacted> ;{id = 19036 (ksk), size = 2048b}
[1584216438] unbound[30708:0] info: file /var/lib/unbound/root.key
[1584216438] unbound[30708:0] info: last_queried: 1584203277 Sat Mar 14 16:27:57 2020
[1584216438] unbound[30708:0] info: last_success: 1584203277 Sat Mar 14 16:27:57 2020
[1584216438] unbound[30708:0] info: next_probe_time: 1584242781 Sun Mar 15 03:26:21 2020
[1584216438] unbound[30708:0] info: query_interval: 43200
[1584216438] unbound[30708:0] info: retry_time: 8640
[1584216438] unbound[30708:0] info: query_failed: 0
[1584216438] unbound[30708:0] info: [ VALID ] . 172800 IN DNSKEY 257 3 8 <redacted> ;{id = 20326 (ksk), size = 2048b} ;;state:2 ;;pending_count:0 last:Sat Mar 14 16:27:53 2020
[1584216438] unbound[30708:0] info: [ MISSING ] . 172800 IN DNSKEY 257 3 8 <redacted> ;{id = 19036 (ksk), size = 2048b} ;;state:3 ;;pending_count:0 last:Sat Mar 14 16:27:53 2020
[1584216438] unbound[30708:0] debug: validator nsec3cfg keysz 1024 mxiter 150
[1584216438] unbound[30708:0] debug: validator nsec3cfg keysz 2048 mxiter 500
[1584216438] unbound[30708:0] debug: validator nsec3cfg keysz 4096 mxiter 2500
[1584216438] unbound[30708:0] notice: init module 2: iterator
[1584216438] unbound[30708:0] debug: target fetch policy for level 0 is 3
[1584216438] unbound[30708:0] debug: target fetch policy for level 1 is 2
[1584216438] unbound[30708:0] debug: target fetch policy for level 2 is 1
[1584216438] unbound[30708:0] debug: target fetch policy for level 3 is 0
[1584216438] unbound[30708:0] debug: target fetch policy for level 4 is 0
[1584216438] unbound[30708:0] debug: donotq: 127.0.0.0/8
[1584216438] unbound[30708:0] debug: EDNS known options:
[1584216438] unbound[30708:0] debug: Code: Bypass_cache_stage: Aggregate_mesh:
[1584216438] unbound[30708:0] debug: edns-cli NO
有什么方法可以知道这个过程为什么会收到一个SIGKILL？