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Merge pull request #890 from awh/use_container_name_as_hostname

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Use container name as hostname

Closes #750.
This commit is contained in:
Matthias Radestock committed 2015-06-11 12:35:46 +01:00
2 parents e1c07dce3f 12fc760e4a
commit e96cde1872
9 files changed
+136 -18
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270_use_name_as_hostname_test.sh
Executable
+36
View File
@@ -0,0 +1,36 @@
#! /bin/bash
. ./config.sh
NAME=c1
DOMAIN=weave.local.
HOSTNAME=$NAME-hostname.$DOMAIN
# Docker inspect hostname + domainname of container $2 on host $1
docker_inspect_fqdn() {
docker_on $1 inspect --format='{{.Config.Hostname}}.{{.Config.Domainname}}' $2
}
# Start container with args $2.. and assert fqdn of $1
assert_expected_fqdn() {
EXPECTED_FQDN=$1
shift
start_container_with_dns $HOST1 "$@"
assert "docker_inspect_fqdn $HOST1 $NAME" $EXPECTED_FQDN
docker_on $HOST1 rm -f $NAME
}
start_suite "Use container name as hostname"
weave_on $HOST1 launch -iprange 10.2.0.0/24
assert_expected_fqdn "$NAME.$DOMAIN" --name=$NAME
assert_expected_fqdn "$NAME.$DOMAIN" --name $NAME
assert_expected_fqdn "$HOSTNAME" --name=$NAME -h $HOSTNAME
assert_expected_fqdn "$HOSTNAME" --name=$NAME --hostname=$HOSTNAME
assert_expected_fqdn "$HOSTNAME" --name=$NAME --hostname $HOSTNAME
assert_expected_fqdn "$HOSTNAME" -h $HOSTNAME --name=$NAME
assert_expected_fqdn "$HOSTNAME" --hostname=$HOSTNAME --name=$NAME
assert_expected_fqdn "$HOSTNAME" --hostname $HOSTNAME --name=$NAME
end_suite
nameserver/http.go
+4
View File
@@ -34,6 +34,10 @@ func ServeHTTP(listener net.Listener, version string, server *DNSServer, domain
fmt.Fprintln(w, db.Status())
})
muxRouter.Methods("GET").Path("/domain").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
fmt.Fprintln(w, db.Domain())
})
muxRouter.Methods("PUT").Path("/name/{id:.+}/{ip:.+}").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
reqError := func(msg string, logmsg string, logargs ...interface{}) {
httpErrorAndLog(Warning, w, msg, http.StatusBadRequest, logmsg, logargs...)
nameserver/server.go
+1
View File
@@ -15,6 +15,7 @@ import (
const (
DefaultServerPort = 53 // The default server port
DefaultHTTPPort = 6785 // The default http port
DefaultCLICfgFile = "/etc/resolv.conf" // default "resolv.conf" file to try to load
DefaultLocalTTL = 30 // default TTL for responses for local domain queries
DefaultUDPBuflen = 4096 // bigger than the default 512
prog/weavedns/main.go
+1 -1
View File
@@ -46,7 +46,7 @@ func main() {
flag.StringVar(&domain, "domain", weavedns.DefaultLocalDomain, "local domain (ie, 'weave.local.')")
flag.IntVar(&wait, "wait", 0, "number of seconds to wait for interface to be created and come up")
flag.IntVar(&dnsPort, "dnsport", weavedns.DefaultServerPort, "port to listen to DNS requests")
flag.IntVar(&httpPort, "httpport", 6785, "port to listen to HTTP requests")
flag.IntVar(&httpPort, "httpport", weavedns.DefaultHTTPPort, "port to listen to HTTP requests")
flag.IntVar(&cacheLen, "cache", weavedns.DefaultCacheLen, "cache length")
flag.IntVar(&ttl, "ttl", weavedns.DefaultLocalTTL, "TTL (in secs) for responses for local names")
flag.BoolVar(&watch, "watch", true, "watch the docker socket for container events")
proxy/create_container_interceptor.go
+35 -2
View File
@@ -3,12 +3,14 @@ package proxy
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"strings"
"github.com/fsouza/go-dockerclient"
. "github.com/weaveworks/weave/common"
"github.com/weaveworks/weave/nameserver"
)
type createContainerInterceptor struct{ proxy *Proxy }
@@ -43,7 +45,7 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
if err := i.setWeaveWaitEntrypoint(container.Config); err != nil {
return err
}
if err := i.setWeaveDNS(&container); err != nil {
if err := i.setWeaveDNS(&container, r); err != nil {
return err
}
}
@@ -78,7 +80,7 @@ func (i *createContainerInterceptor) setWeaveWaitEntrypoint(container *docker.Co
return nil
}
func (i *createContainerInterceptor) setWeaveDNS(container *createContainerRequestBody) error {
func (i *createContainerInterceptor) setWeaveDNS(container *createContainerRequestBody, r *http.Request) error {
if !i.proxy.WithDNS {
return nil
}
@@ -88,9 +90,40 @@ func (i *createContainerInterceptor) setWeaveDNS(container *createContainerReque
if len(container.HostConfig.DNSSearch) == 0 {
container.HostConfig.DNSSearch = []string{"."}
}
name := r.URL.Query().Get("name")
if container.Hostname == "" && name != "" {
container.Hostname = name
container.Domainname = i.getDNSDomain()
}
return nil
}
func (i *createContainerInterceptor) getDNSDomain() (domain string) {
domain = nameserver.DefaultLocalDomain
dnsContainer, err := i.proxy.client.InspectContainer("weavedns")
if err != nil ||
dnsContainer.NetworkSettings == nil ||
dnsContainer.NetworkSettings.IPAddress == "" {
return
}
url := fmt.Sprintf("http://%s:%d/domain", dnsContainer.NetworkSettings.IPAddress, nameserver.DefaultHTTPPort)
resp, err := http.Get(url)
if err != nil || resp.StatusCode != http.StatusOK {
return
}
defer resp.Body.Close()
b, err := ioutil.ReadAll(resp.Body)
if err != nil {
return
}
return string(b)
}
func (i *createContainerInterceptor) InterceptResponse(r *http.Response) error {
return nil
}
site/proxy.md
+3 -1
View File
@@ -127,7 +127,9 @@ option, i.e.
Now any containers started via the proxy, and with a `WEAVE_CIDR=...`
environment variable (or even without it, if IPAM is
[configured](#ipam)), will use weaveDNS for name resolution.
[configured](#ipam)), will use weaveDNS for name resolution. If not
provided, the hostname will default to the container name and will be
registered in weaveDNS.
## <a name="multi-host"></a>Multi-host example
site/weavedns.md
+14 -6
View File
@@ -29,20 +29,28 @@ other over the weave network. One such container needs to be started
on every weave host, by invoking the weave script command
`launch-dns`. Application containers are then instructed to use
weaveDNS as their nameserver by supplying the `--with-dns` option when
starting them. Giving any container a hostname in the `.weave.local`
domain registers it in weaveDNS. For example:
starting them; containers so started also automatically register their
container name in the weaveDNS domain. For example:
```bash
$ weave launch
$ weave launch-dns 10.2.254.1/24
$ weave run 10.2.1.25/24 -ti -h pingme.weave.local ubuntu
$ shell1=$(weave run --with-dns 10.2.1.26/24 -ti -h ubuntu.weave.local ubuntu)
$ weave run --with-dns 10.2.1.25/24 -ti --name=pingme ubuntu
$ shell1=$(weave run --with-dns 10.2.1.26/24 -ti --name=ubuntu ubuntu)
$ docker attach $shell1
root@ubuntu:/# ping pingme
...
```
If you start an application container sans `--with-dns` you can still register
it in weaveDNS simply by giving the container a hostname in the
`.weave.local.` domain:
```
$ weave run 10.2.1.25/24 -ti -h pingme.weave.local ubuntu
```
Each weaveDNS container started with `launch-dns` needs to be given
its own, unique, IP address, in a subnet that is a) common to all
weaveDNS containers, b) disjoint from the application subnets, and c)
@@ -55,7 +63,7 @@ use weaveDNS on a second host we would run:
```bash
host2$ weave launch $HOST1
host2$ weave launch-dns 10.2.254.2/24
host2$ shell2=$(weave run --with-dns 10.2.1.36/24 -ti -h ubuntu2.weave.local ubuntu)
host2$ shell2=$(weave run --with-dns 10.2.1.36/24 -ti --name=ubuntu2 ubuntu)
host2$ docker attach $shell2
root@ubuntu2:/# ping pingme
@@ -110,7 +118,7 @@ Returning to our earlier example, let us start an additional `pingme`
container, this time on the 2nd host, and then run some ping tests...
```bash
host2$ weave run 10.2.1.35/24 -ti -h pingme.weave.local ubuntu
host2$ weave run --with-dns 10.2.1.35/24 -ti --name=pingme ubuntu
host2$ docker attach $shell2
root@ubuntu2:/# ping -nq -c 1 pingme
test/630_proxy_dns_test.sh
+6 -4
View File
@@ -4,15 +4,17 @@
C1=10.2.0.78
C2=10.2.0.34
NAME=seetwo.weave.local
C1_NAME=c1.weave.local
C2_NAME=seetwo.weave.local
start_suite "Proxy registers containers with dns"
weave_on $HOST1 launch-dns 10.2.254.1/24
weave_on $HOST1 launch-proxy --with-dns
proxy docker_on $HOST1 run -e WEAVE_CIDR=$C2/24 -dt --name=c2 -h $NAME $SMALL_IMAGE /bin/sh
proxy docker_on $HOST1 run -e WEAVE_CIDR=$C1/24 -dt --name=c1 $DNS_IMAGE /bin/sh
proxy docker_on $HOST1 run -e WEAVE_CIDR=$C2/24 -dt --name=c2 -h $C2_NAME $DNS_IMAGE /bin/sh
proxy docker_on $HOST1 run -e WEAVE_CIDR=$C1/24 -dt --name=c1 $DNS_IMAGE /bin/sh
assert_dns_record $HOST1 c1 $NAME $C2
assert_dns_record $HOST1 c1 $C2_NAME $C2
assert_dns_record $HOST1 c2 $C1_NAME $C1
end_suite
weave
+36 -4
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@@ -648,16 +648,45 @@ dns_args() {
docker_bridge_ip
DNS_ARG="--dns $DOCKER_BRIDGE_IP"
DNS_SEARCH_ARG="--dns-search=."
for arg in "$@" ; do
case $arg in
NAME_ARG=""
HOSTNAME_SPECIFIED=false
while [ $# -gt 0 ] ; do
case "$1" in
--dns-search=*)
DNS_SEARCH_ARG=""
shift
;;
--name)
NAME_ARG="$2"
shift 2
;;
--name=*)
NAME_ARG="${1#*=}"
shift
;;
-h|--hostname|--hostname=*)
HOSTNAME_SPECIFIED=true
shift
;;
*)
shift
;;
esac
done
DNS_ARGS="$DNS_ARG $DNS_SEARCH_ARG"
if [ -n "$NAME_ARG" -a "$HOSTNAME_SPECIFIED" = "false" ] ; then
DNS_ARGS="$DNS_ARGS --hostname=$NAME_ARG.$(dns_domain)"
fi
}
# Use the weaveDNS REST API to determine the local domain. If weaveDNS is not
# running, return the default value ('weave.local.')
dns_domain() {
if DOMAIN=$(http_call $DNS_CONTAINER_NAME $DNS_HTTP_PORT GET /domain 2>/dev/null) ; then
echo $DOMAIN
else
echo 'weave.local.'
fi
}
# Print an error to stderr and return with an indicative exit status
@@ -687,9 +716,9 @@ with_container_fqdn() {
COMMAND="$2"
shift 2
CONTAINER_FQDN=$(docker inspect --format='{{.Config.Hostname}}.{{.Config.Domainname}}.' $CONTAINER 2>/dev/null) || return 0
CONTAINER_FQDN=$(docker inspect --format='{{.Config.Hostname}}.{{.Config.Domainname}}' $CONTAINER 2>/dev/null) || return 0
if echo "$CONTAINER_FQDN" | grep -qv '\.\.$' ; then
if echo "$CONTAINER_FQDN" | grep -Eq '[^.]+\..+' ; then
$COMMAND "$CONTAINER" "$CONTAINER_FQDN" "$@"
fi
}
@@ -1069,6 +1098,9 @@ case "$COMMAND" in
dns_args "$@"
echo -n $DNS_ARGS
;;
dns-domain)
echo $(dns_domain)
;;
docker-bridge-ip)
docker_bridge_ip
echo -n $DOCKER_BRIDGE_IP