书接上文。
在《使用nomad实现集群管理和微服务部署调度》一文中，我们介绍了使用nomad进行集群管理和工作负载调度的轻量级方案（相较于Kubernetes方案）。在本文中，我们继续对方案进行延展，介绍一下在nomad集群中工作负载版本升级的一些常用模式和实现方法，包括滚动升级、蓝绿部署和金丝雀部署。
一. 初始状态
这里我们利用基于tcp+sni路由(listener端口为9996)的httpsbackend-sni-1的job作为演示job，该job的初始部署nomad job文件为：httpsbackend-tcp-sni-1.nomad (注：不同的是，这里将count初始值改为了3)。
当前httpsbackend-sni-1这个job的状态如下：
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T10:57:29+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 3 0 3 0
Allocations
ID Node ID Task Group Version Desired Status Created Modified
7ac186b8 7acdd7bc httpsbackend-sni-1 22 run running 1m18s ago 1m1s ago
8a79085f c281658a httpsbackend-sni-1 22 run running 1m18s ago 46s ago
f9ffef32 9e3ef19f httpsbackend-sni-1 22 run running 1m18s ago 59s ago
0ed95591 9e3ef19f httpsbackend-sni-1 20 stop complete 5d19h ago 7m16s ago
604d2151 9e3ef19f httpsbackend-sni-1 20 stop complete 5d19h ago 7m16s ago
06404fff 7acdd7bc httpsbackend-sni-1 20 stop complete 5d20h ago 7m14s ago
fabio路由表如下：
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.0
接下来，我们就以这个job为基础，使用各种版本升级模式对其进行更新。
二. 滚动更新(rolling update)
下面是blog.itaysk.com上一篇文章中的有关滚动更新的示意图：
可以大致看出所谓滚动更新就是对目标环境下老版本的程序进行逐批的替换，每批的数量可以是1，也可以大于1，根据目标实例的个数自定义。替换过程中，新老版本是并存的，直到所有目标实例都被替换为新版本。
nomad支持通过在job描述文件中增加update配置来支持滚动更新。我们创建httpsbackend-tcp-sni-1-rolling-update.nomad，考虑篇幅，这里仅列出与httpsbackend-tcp-sni-1.nomad的差异：
# diff httpsbackend-tcp-sni-1-rolling-update.nomad ./httpsbackend-tcp-sni-1.nomad
14,19d13
< update {
< max_parallel = 1
< min_healthy_time = "30s"
< healthy_deadline = "5m"
< }
<
23c17
< image = "bigwhite/httpsbackendservice:v1.0.1"
---
> image = "bigwhite/httpsbackendservice:v1.0.0"
新job nomad文件使用了v1.0.1版本的httpsbackendservice image，增加了update {…}配置环节，其中的max_parallel指示的是滚动更新每批更新的数量，这里是1，也就是说一批仅用新版本替换一个老版本实例。
执行滚动更新：
# nomad job run httpsbackend-tcp-sni-1-rolling-update.nomad
==> Monitoring evaluation "8d39ab53"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "348ef16b"
Allocation "88c1a29e" created: node "7acdd7bc", group "httpsbackend-sni-1"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "8d39ab53" finished with status "complete"
httpsbackendservice job的task group有三个task实例，因此更新需要一些时间，我们在更新过程中查看job status：
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T13:06:35+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 3 0 4 0
Latest Deployment
ID = 348ef16b
Status = running
Description = Deployment is running
Deployed
Task Group Desired Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 3 1 0 0 2019-04-08T13:16:35+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
88c1a29e 7acdd7bc httpsbackend-sni-1 23 run running 44s ago 41s ago
7ac186b8 7acdd7bc httpsbackend-sni-1 22 run running 2h9m ago 2h9m ago
8a79085f c281658a httpsbackend-sni-1 22 run running 2h9m ago 2h9m ago
f9ffef32 9e3ef19f httpsbackend-sni-1 22 stop complete 2h9m ago 44s ago
我们看到nomad job status命令输出的信息中多出了“Latest Deployment”一个小节，在该小节中，我们看到了一个ID为348ef16b的deployment正在run。这个deployment对应的就是这次的滚动更新，我们看到下面的allocations列表中，一个version为22的allocation已经stop，一个version为23的allocation已经run，这说明nomad已经完成了一个task实例的版本升级。
我们再来查看一下job执行的最终状态：
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T13:06:35+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 3 0 6 0
Latest Deployment
ID = 348ef16b
Status = successful
Description = Deployment completed successfully
Deployed
Task Group Desired Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 3 3 3 0 2019-04-08T13:18:43+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
da1b545b 7acdd7bc httpsbackend-sni-1 23 run running 34s ago 2s ago
44da5693 9e3ef19f httpsbackend-sni-1 23 run running 1m25s ago 36s ago
88c1a29e 7acdd7bc httpsbackend-sni-1 23 run running 2m10s ago 1m26s ago
7ac186b8 7acdd7bc httpsbackend-sni-1 22 stop complete 2h11m ago 1m24s ago
8a79085f c281658a httpsbackend-sni-1 22 stop complete 2h11m ago 34s ago
f9ffef32 9e3ef19f httpsbackend-sni-1 22 stop complete 2h11m ago 2m10s ago
我们看到job执行的最终结果：ID为348ef16b的deployment执行成功；所有version 为23的allocations都处于running状态。task group的三个task实例都处于healthy状态。这说明滚动更新成功了！
我们也可以通过nomad提供的deployment子命令查看deployment的状态，deployment id作为命令参数：
# nomad deployment list
ID Job ID Job Version Status Description
348ef16b httpsbackend-sni-1 23 successful Deployment completed successfully
# nomad deployment status 348ef16b
ID = 348ef16b
Job ID = httpsbackend-sni-1
Job Version = 23
Status = successful
Description = Deployment completed successfully
Deployed
Task Group Desired Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 3 3 3 0 2019-04-08T13:18:43+08:00
滚动更新后的路由：
测试一下部署成功的新版本服务：
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.1
三. 金丝雀部署(canary deployment)
金丝雀部署是另外一种十分有用的部署模式，下面示意图来自blog.itaysk.com：
金丝雀 (Canary)得名于矿工的一个工作习惯：下矿洞前，先会放一只金丝雀进去探测是否有有毒气体，看金丝雀能否活下来。如果金丝雀活下来，则继续下矿操作；否则停止下矿。金丝雀部署亦是先部署少量新版本的服务实例，发布后，开发者可简单地通过手工测试验证新版本实例，又或通过完善的自动化测试基础设施对新版本实例进行详尽验证；甚至是直接接收部分生产流量以充分验证新版本功能、稳定性、性能等，以给予开发者更多信心。如果金丝雀实例通过全部测试验证，则把所有老版本全部升级为新版本。如果金丝雀测试失败，则直接回退金丝雀实例，发布失败。
nomad支持两种模式的canary部署：既支持部署canary实例去直接接收生产流量（按比例权重），也可以将其与生产实例隔离开来（利用路由）单独测试验证，下面分别说说这两种模式。
1. 部署canary实例去直接接收生产流量（按比例权重）
我们创建一个新的nomad job文件：httpsbackend-tcp-sni-1-canary-1.nomad
# diff httpsbackend-tcp-sni-1-canary-1.nomad httpsbackend-tcp-sni-1-rolling-update.nomad
18d17
< canary = 1
24c23
< image = "bigwhite/httpsbackendservice:v1.0.2"
---
> image = "bigwhite/httpsbackendservice:v1.0.1"
我们看到除了新版本task使用v1.0.2版image之外，最大的不同就是在update {…}配置区域增加了一行：
canary = 1
我们来plan一下该nomad文件：
# nomad job plan httpsbackend-tcp-sni-1-canary-1.nomad
+/- Job: "httpsbackend-sni-1"
+/- Task Group: "httpsbackend-sni-1" (1 canary, 3 ignore)
+/- Update {
AutoRevert: "false"
+/- Canary: "0" => "1"
HealthCheck: "checks"
HealthyDeadline: "300000000000"
MaxParallel: "1"
MinHealthyTime: "30000000000"
ProgressDeadline: "600000000000"
}
+/- Task: "httpsbackend-sni-1" (forces create/destroy update)
+/- Config {
+/- image: "bigwhite/httpsbackendservice:v1.0.1" => "bigwhite/httpsbackendservice:v1.0.2"
logging[0][type]: "json-file"
port_map[0][https]: "7777"
}
Scheduler dry-run:
- All tasks successfully allocated.
... ...
我们看到nomad分析的结果是：需要创建一个canary实例，忽略三个已经存在的旧版本task实例。同时task group的canary属性从“0”变为了“1”。
我们来run该job：
# nomad job run httpsbackend-tcp-sni-1-canary-1.nomad
==> Monitoring evaluation "0494a8a9"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "3e541fb3"
Allocation "4d678e67" created: node "c281658a", group "httpsbackend-sni-1"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "0494a8a9" finished with status "complete"
查看job的run状态：
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T21:04:49+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 4 0 6 0
Latest Deployment
ID = 3e541fb3
Status = running
Description = Deployment is running but requires promotion
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 false 3 1 1 0 0 2019-04-08T21:14:49+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
4d678e67 c281658a httpsbackend-sni-1 24 run running 31s ago 15s ago
da1b545b 7acdd7bc httpsbackend-sni-1 23 run running 7h57m ago 7h56m ago
44da5693 9e3ef19f httpsbackend-sni-1 23 run running 7h57m ago 7h57m ago
88c1a29e 7acdd7bc httpsbackend-sni-1 23 run running 7h58m ago 7h58m ago
# nomad deployment status 3e541fb3
ID = 3e541fb3
Job ID = httpsbackend-sni-1
Job Version = 24
Status = running
Description = Deployment is running but requires promotion
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 false 3 1 1 1 0 2019-04-08T21:15:35+08:00
我们看到：
-
处于running状态的allocations变成了4个，但是只有一个是version = 24的，其余都为version = 23。version = 24这个显然是我们新部署的canary实例，而另外三个则为原有的老版本实例。
-
在Deployment输出信息中，我们看到了一个描述信息：“Deployment is running but requires promotion”，意思是此次用于部署canary实例的Deployment已经running了，但是还未到最终状态，还需要promote命令。只有promote后，整个的更新工作才算是ok。
下面是canary部署后的fabio的路由：
我们看到canary实例与其余老版本的路由规则是一致的，并平分的负载权重。也就是说新部署的canary实例与老版本实例一起承载生产流量(canary实例占25%的权重)，我们来验证一下：
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.1
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.1
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.1
我们看到第一个请求的流量就打到了我们部署的Canary实例身上了。
如果经过一段时间的验证后，证明canary实例满足要求，我们就要继续推动部署的进程使得该nomad deployment走向最终状态：即将老版本的实例都升级为新版本。
# nomad deployment promote 3e541fb3
==> Monitoring evaluation "b5e29b1a"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "3e541fb3"
Allocation "085a518e" created: node "7acdd7bc", group "httpsbackend-sni-1"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "b5e29b1a" finished with status "complete"
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T21:04:49+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 3 0 9 0
Latest Deployment
ID = 3e541fb3
Status = successful
Description = Deployment completed successfully
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 true 3 1 3 3 0 2019-04-08T21:30:54+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
40276d89 9e3ef19f httpsbackend-sni-1 24 run running 56s ago 11s ago
085a518e 7acdd7bc httpsbackend-sni-1 24 run running 1m49s ago 58s ago
4d678e67 c281658a httpsbackend-sni-1 24 run running 16m17s ago 1m49s ago
da1b545b 7acdd7bc httpsbackend-sni-1 23 stop complete 8h12m ago 56s ago
44da5693 9e3ef19f httpsbackend-sni-1 23 stop complete 8h13m ago 1m48s ago
88c1a29e 7acdd7bc httpsbackend-sni-1 23 stop complete 8h14m ago 1m47s ago
通过deployment promote命令使得canary deployment进程继续推进，直到将所有老版本的实例都用canary实例替换掉。也就是我们最终看到的上面的version = 24的allocations都处于running状态，并且一共是三个实例。
我们再来测试一下升级后的服务：
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
我们看到：所有实例都升级到了v1.0.2版本。
2.将canary实例与生产实例隔离开来（利用路由）单独测试验证
如果开发者对自己的代码很有信心，不需要将canary实例暴露在生产流量中去验证，nomad也支持将canary实例与生产实例隔离开来（利用路由）单独测试验证。
我们基于httpsbackend-tcp-sni-1-canary-1.nomad改写出一个httpsbackend-tcp-sni-1-canary-2.nomad：
# diff httpsbackend-tcp-sni-1-canary-2.nomad httpsbackend-tcp-sni-1-canary-1.nomad
24c24
< image = "bigwhite/httpsbackendservice:v1.0.3"
---
> image = "bigwhite/httpsbackendservice:v1.0.2"
43d42
< canary_tags = ["urlprefix-canary.mysite-sni-1.com/ proto=tcp+sni"]
我们看到，在新的job文件中，我们除了将image版本升级为v1.0.3，我们还在service{…}配置区域增加了下面这行：
canary_tags = ["urlprefix-canary.mysite-sni-1.com/ proto=tcp+sni"]
该配置是canary实例专有的，这里我们通过在canary_tags为canary实例单独定义了路由，以免和老版本实例共享路由分担生产流量。
我们照例运行该job并查看job执行后的status：
# nomad job run httpsbackend-tcp-sni-1-canary-2.nomad
==> Monitoring evaluation "44e36161"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "e43d2551"
Allocation "73319890" created: node "7acdd7bc", group "httpsbackend-sni-1"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "44e36161" finished with status "complete"
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T21:35:03+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 4 0 9 0
Latest Deployment
ID = e43d2551
Status = running
Description = Deployment is running but requires promotion
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 false 3 1 1 1 0 2019-04-08T21:45:51+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
73319890 7acdd7bc httpsbackend-sni-1 25 run running 2m24s ago 1m36s ago
40276d89 9e3ef19f httpsbackend-sni-1 24 run running 17m18s ago 16m33s ago
085a518e 7acdd7bc httpsbackend-sni-1 24 run running 18m11s ago 17m20s ago
4d678e67 c281658a httpsbackend-sni-1 24 run running 32m39s ago 18m11s ago
这个输出信息和之前的canary模式差别不大。但是从fabio路由表上我们看到如下信息：
fabio单独为canary实例生成了一个新路由，以区别于老版本的三个实例的路由。
开发人员单独测试canary实例时，可以通过下面方式注入流量:
# curl -k https://canary.mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.3
而生产流量依旧流入老版本的实例中：
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.2
canary实例经过测试验证后，同样可以通过promote完成对老版本的升级部署：
# nomad deployment promote e43d2551
==> Monitoring evaluation "34a67391"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "e43d2551"
Allocation "193cbc2f" created: node "c281658a", group "httpsbackend-sni-1"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "34a67391" finished with status "complete"
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-08T21:35:03+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 3 0 12 0
Latest Deployment
ID = e43d2551
Status = successful
Description = Deployment completed successfully
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 true 3 1 3 3 0 2019-04-08T21:58:24+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
528a75bd 7acdd7bc httpsbackend-sni-1 25 run running 51s ago 10s ago
193cbc2f c281658a httpsbackend-sni-1 25 run running 1m39s ago 52s ago
73319890 7acdd7bc httpsbackend-sni-1 25 run running 13m31s ago 1m39s ago
40276d89 9e3ef19f httpsbackend-sni-1 24 stop complete 28m25s ago 50s ago
085a518e 7acdd7bc httpsbackend-sni-1 24 stop complete 29m18s ago 1m38s ago
4d678e67 c281658a httpsbackend-sni-1 24 stop complete 43m46s ago 1m39s ago
同时，canary实例在fabiolb上的路由也会自动删除掉。canary_tags在promote后将不再起作用，fabio使用的是tags。
# curl -k https://canary.mysite-sni-1.com:9996/
curl: (35) gnutls_handshake() failed: The TLS connection was non-properly terminated.
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.3
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.3
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.3
四. 蓝绿部署(blue-green deployment)
下面的蓝绿部署模式的示意图同样来自blog.itaysk.com：
与之前的滚动更新、金丝雀部署不同的是，蓝绿部署需要“两套”环境，通过路由指向来切换流量究竟经过哪套环境。
但是在nomad官方关于blue-green部署的例子中，nomad实际只维护了一套环境，并且例子中是利用nomad的canary机制来实现的蓝绿部署。这种实现方式并非严格遵循“蓝绿部署”的公认的定义。
但nomad官方对于blue-green部署的理解似乎仅限如此。我们也来看一下nomad的这种“全量金丝雀”的蓝绿方案：
我们创建httpsbackend-tcp-sni-1-blue-green.nomad文件，重点内容差异如下：
# diff httpsbackend-tcp-sni-1-blue-green.nomad httpsbackend-tcp-sni-1-canary-1.nomad
18c18
< canary = 3
---
> canary = 1
24c24
< image = "bigwhite/httpsbackendservice:v1.0.4"
---
> image = "bigwhite/httpsbackendservice:v1.0.2"
我们看到这里canary = 3，与count值相同，这也是将其称为“全量金丝雀”的原因。
使用该文件部署新版本实例：
# nomad job run httpsbackend-tcp-sni-1-blue-green.nomad
==> Monitoring evaluation "7a5074f3"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "3c8740f2"
Allocation "338ee344" created: node "c281658a", group "httpsbackend-sni-1"
Allocation "3dec73d2" created: node "9e3ef19f", group "httpsbackend-sni-1"
Allocation "e6975673" created: node "9e3ef19f", group "httpsbackend-sni-1"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "7a5074f3" finished with status "complete"
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-09T13:38:49+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 6 0 12 0
Latest Deployment
ID = 3c8740f2
Status = running
Description = Deployment is running but requires promotion
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 false 3 3 3 3 0 2019-04-09T13:49:41+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
338ee344 c281658a httpsbackend-sni-1 26 run running 57s ago 5s ago
3dec73d2 9e3ef19f httpsbackend-sni-1 26 run running 57s ago 11s ago
e6975673 9e3ef19f httpsbackend-sni-1 26 run running 57s ago 10s ago
528a75bd 7acdd7bc httpsbackend-sni-1 25 run running 15h52m ago 15h51m ago
193cbc2f c281658a httpsbackend-sni-1 25 run running 15h52m ago 15h52m ago
73319890 7acdd7bc httpsbackend-sni-1 25 run running 16h4m ago 15h52m ago
部署ok后，6个实例共同接收生产流量。当然我们也可以通过canary_tags为新的部署设定不同路由，选择哪一种要看部署新实例后打算对新实例如何进行测试。
测试验证ok后，像canary deployment一样，通过promote命令用新版本替换老版本。
# nomad deployment promote 3c8740f2
==> Monitoring evaluation "fad3a69b"
Evaluation triggered by job "httpsbackend-sni-1"
Evaluation within deployment: "3c8740f2"
Evaluation status changed: "pending" -> "complete"
==> Evaluation "fad3a69b" finished with status "complete"
# nomad job status httpsbackend-sni-1
ID = httpsbackend-sni-1
Name = httpsbackend-sni-1
Submit Date = 2019-04-09T13:38:49+08:00
Type = service
Priority = 50
Datacenters = dc1
Status = running
Periodic = false
Parameterized = false
Summary
Task Group Queued Starting Running Failed Complete Lost
httpsbackend-sni-1 0 0 3 0 15 0
Latest Deployment
ID = 3c8740f2
Status = successful
Description = Deployment completed successfully
Deployed
Task Group Promoted Desired Canaries Placed Healthy Unhealthy Progress Deadline
httpsbackend-sni-1 true 3 3 3 3 0 2019-04-09T13:49:41+08:00
Allocations
ID Node ID Task Group Version Desired Status Created Modified
338ee344 c281658a httpsbackend-sni-1 26 run running 4m43s ago 15s ago
3dec73d2 9e3ef19f httpsbackend-sni-1 26 run running 4m43s ago 15s ago
e6975673 9e3ef19f httpsbackend-sni-1 26 run running 4m43s ago 15s ago
528a75bd 7acdd7bc httpsbackend-sni-1 25 stop complete 15h55m ago 14s ago
193cbc2f c281658a httpsbackend-sni-1 25 stop complete 15h56m ago 15s ago
73319890 7acdd7bc httpsbackend-sni-1 25 stop complete 16h8m ago 14s ago
测试结果：
# curl -k https://mysite-sni-1.com:9996/
this is httpsbackendservice, version: v1.0.4
如果要快速切换回原来的版本，可以使用：
nomad job revert httpsbackend-sni-1 {old_allocation_version}
五. 其他
本文涉及到的nomad job文件源码可在这里下载。
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